Journal of Biology 2016

ALSO IN THE JOURNAL

VOLUME C | ISSUE 1 | 2016

SPECIAL FEATURE The Year in Biology FEATURED STUDENT RESEARCH An investigation into factors that influence enamel thickness in premolar teeth in the guenons (tribe Cercopithecini)

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SENIOR STAFF

CONTRIBUTORS

Crystal Wu ‘16

Ginger Lau ‘19

Yan Zhang ‘16

Angie Yang

Yi Chen ‘16

Ashley Loke ‘18

Anusha Bishop ‘16 Maya Goodwin ‘16

FACULTY CONSULTANT

Aliyah Taylor ‘16

Erin O’Leary, PhD

PRODUCTION EDITOR Nanami Kubota ‘16 Olivia Guan ‘17

2016

Sharon Yu ‘17

Volume C

THE BRONX HIGH SCHOOL of SCIENCE 75 West 205th Street Bronx, New York 10468 Telephone: (718) 817 -7700 Fax: (718) 733 -7951 www.bxscience.edu JEAN M. DONAHUE, PhD Principal ALLISON DAVIS, PhD Assistant Principal The Journal of Biology is published annually by the students of the Bronx High School of Science

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COMMENTARY

What is Evolution ?

by Ginger Lau ‘19 and Yan Fan ‘19 Considering the age of the Earth, which is about 4.6 billion years old, and the approximate amount of time humans have occupied it, recorded history covers only an insignificant amount of the entire lifespan of the Earth. In light of this, how would we know what the Earth looked like before us?

How do we know how living things have evolved over time? The evolution of organisms is so gradual that no one would be able to notice a change in one lifespan, or even two. However, scientists are able to come up with evidence of evolution through small clues left behind. By putting this evidence together, a whole new face of the world is unveiled.

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The Year In Biology By Yan Zhang pg. 29 - 33

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Evolution (n): Evolution is the cumulative modification occurring in a species over many generations. Dominant traits that allow species to thrive in their environment are selected for resulting in change in the species as a whole.

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POETRY

Natural Selection

By Maya Goodwin ‘16

The tooth is a weapon made of white stone used by the mammals to chomp plant and bone A bear named Fifi clung to a branch among the heavy boughs she sang and danced With her teeth bared she fell on a large fruit Used her chompers to scoop the juicy loot When along came a bee, a yellow bee Buzz buzz buzz! said the bee quite angrily He had to give all his ethyl deate away to the nurse bees so they could make royal jelly. But Fifi didn’t care she was just a very hungry bear The bee buzzed and buzzed and then stung Fifi!

Ow! cried Fifi and fell from the tall tree Then she died; her offspring would live with ease because they knew not to bother the bees

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INTERVIEW

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broken DNA strand invading another gene. There might be one event in every 10^15 cells that result in oncogenesis, but if you wanted to alter a billion cells per patient and you want to do that to a million patients, then that is 10 ^15 and you have already given a patient cancer. But it would be better if we Interviewed by: Yi Chen ‘16 and Ginger Lau ‘19 had a different technology for editing genes. Some people have played around with the idea of trying to make a CRISPR type recombinase. Recombinase is Kevin Esvelt is director of the Sculpting Evolution when they splice DNA and hold onto both ends until Group and an assistant professor at MIT Media lab they piece them back together. More generally with as the leader of the Sculpting Evolution group. Dr. CRISPR, we are figuring out how to apply it in Esvelt is working to invent and study the evolution more organisms because it seems to work in pretty of ecosystems. At the Wyss Institute, he worked much every organism we test, but we still have to with George Church to develop CRISPR/Cas9. We optimize how much of the gene is altered, things were able to contact him and ask him some queslike that. tions.

Q. On your website, you said that you need to use Q. What is CRISPR? this technology with wisdom and humility. Can A. CRISPR/Cas9 is a protein that you can give to a you expand on that?

RNA sequence that will cause it to bind to respecA. There has been a lot of question in the media tively any DNA sequence you want in a specific lately about the possibility of using CRISPR to the manner. So all biology is, is selective stickiness, but human germ line to alter future generations and DNA, RNA, and proteins are the three major classes there is a debate about ethics and so will be for of sequences that make up polymers; most stuff in some time until we can use CRISPR. Right now, the the cell has to do with at least one of those. Now technology isn’t nearly specific enough, and it won’t with CRISPR, you can then direct pretty much any be for some time, and so it is very hard to improve one of those to interact with any others in any parthat ethically, because you are working on, well, ticular site. potentially humans. In terms of identifying whether if something goes wrong, you would actually have Q. We read through your articles and we were to create a baby all the way through development to just pretty amazed and we were wondering what make sure you didn’t get something you didn’t exfurther developments or improvements could pect. So using CRISPR is not going to happen anyyou do to this technology? time soon. Since CRISPR can have profoundly drasA. So, there are approximately a billion labs work- tic effects on humanity, we must use this technology ing on CRISPR improvements. Most of them are with wisdom. interested in gene therapy applications, others are interested in utility as a lab tool and honestly it’s Q. Beyond human research, in terms of altering pretty amazing as a lab tool as is. That said, there species as a whole, in genetic engineering we are certainly some areas where we could make it think of altering the one organism, however with even better. So one of the issues is, if you want to CRISPR you can alter the genome of the entire use it for gene therapy, then you have a problem species. Do you think we are far away from alterwith off-target effects. So what if you cut a gene ing the genome of an entire species versus getting you didn’t intend to cut? If this is in a patient, then to the point of editing human genomes? even if it only makes just one wrong cut in the A. I think that we are much closer to using CRISPR wrong cell, that cell becomes pathogenic, then you to alter wild populations than we are to edit the huhave just given that patient cancer. Thus, CRISPR man germ line, not the human genome because we should not be used in the nucleus because even if it have already started doing that. When it comes to perfectly cuts the sequence the way you wanted it to changes that will propagate through generations, we every time with no off-targets whatsoever, which is will use CRISPR on the wild populations before of course not going to happen, then you could still anyone uses CRISPR to create a designer baby. We have a chromosomal rearrangement caused by that have never been faced with the technology that lets

Interview: Dr. Kevin Esvelt

a single laboratory affect the lives of many other people. This raises the issues of the ethics and the practicality. That is, do you even have the right to build these organisms in your laboratory if you don’t tell anyone about it? Because in medical research we have this principle of informed consent whereby people have to indicate that they understand what is the purpose of their study, and the risks.

we edit an organism, no matter how precise, when we change an organism we change it for our own benefit. Since evolution betters an organism’s ability to reproduce and survive, thus even if we could change an organism's, natural selection will just eliminate it. The thing with CRISPR gene drive is that we can intervene in a natural system much more precisely. By using biology, we are speaking the language of nature.

Q. When you think of the reactions to GMO from the public, how do you think we can move forwards and inform people about this?

A. We have to do science completely differently.

Right now, we have this problem with open access science articles. What we’re talking about here is that we have to go much further because opaque science is costly; even if you have access to every journal ever published, you still only see those results after they’ve been written up and gone through peer review. Realistically, we should still be able to see the results even before everything is compiled into a paper. So the problem is that the structure and the cultural norms for sciences is all wrong. It's not that these scientists are not altruistic enough to share their findings because scientists peer review with no acknowledgement or recognition at all, but since technology has evolved, we can definitely do more.

Technology has given us much better ways of communicating science and we should adapt to that.

Q. What are you currently studying?

A. What I'm currently exploring is the possibility of altering the white footed mouse population which is the main reservoir for Lyme disease in America. It is a major problem here and the vast majority occurs when a tick bites a white footed mouse, but if we eradicate the reservoirs of ticks we could decrease cases of Lyme disease. This is case where we can use a gene drive to alter the population. I am also working to study malaria, dengue, and a couple more diseases in mosquitoes.

Q. What is some of your advice regarding research on CRISPR that you learned and what advice do you have for us in terms of trying to cope with failure in research?

A. Most science doesn’t result in what you predict.

Even with CRISPR, some things just fail. Failure most of the time comes from biology’s availability to evolve. Evolution tends to favor many different parts of interaction. Biology is like a circuit with numerous parts working while also being connected.

Trying to treat biology like electrical engineering just doesn’t work because biology is not an isolated circuit.

Q. What do you think the future will be like with CRISPR? A. Historically, we have interacted with the living world using chemistry, physics, and engineering, and so we have a very large ecological impact. To date, we have a tremendous environmental impact due to the limitations of our technology. Whenever

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FEATURED STUDENT RESEARCH

An investigation into factors that influence enamel thickness in premolar teeth in the guenons (tribe Cercopithecini) Maya Goodwin ‘16

Abstract The investigations of the factors that influence enamel thickness in primates provide us insight regarding how natural selection may shape enamel thickness. This study tested whether enamel thickness increases from anterior to posterior teeth, and whether diet or the maximum latitude of species distribution range closely relates to enamel thickness in the guenons (tribe Cercopithecini, family Cercopithecidae). Because guenons are a species-rich tribe, they can be studied as a model of enamel thickness evolution that controls deep phylogenetic divergence. Using ImageJ on Cintiq 13HD tablet, various measurements were taken from 3D ÎźCT-scanned images of virtuallysectioned 30 guenon teeth. Then Absolute Enamel Thickness (AET) and Relative Enamel Thickness (RET) were computed. This study found that differences between sexes, upper/lower jaws, left /right sides of jaws were not significantly significant. However, enamel thickness in PM4 was significantly thicker than that of PM3. Thus, the hypothesis that enamel thickness increases from anterior to posterior teeth was supported. Furthermore this study found significant species differences in AET and RET. The general linear models (GLM) revealed that AET-maximum latitude is expressed as y = 0.013x + 0.27 and the GLM of the RET- maximum latitude of the species range fit was y = 0.42x + 11. These results support my hypothesis. Contrary to my hypothesis, no close relationship between diet and enamel thickness was found. ANOVA on RET show that tooth Position (PM3 or PM4) has the greatest predictable power followed by Species and Maximum Latitude, but the residual of 43.17 indicates that some unknown factor(s) also appear to influence enamel thickness.

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INTRODUCTION Our knowledge regarding the factors that influence the variations in enamel thickness of molar teeth, and to a much lesser extent in premolar teeth, in primates has increased tremendously in the last thirty years or so (Kay 1981; Andrews and Martin 1991; Dumont 1995; Martin et al. 2003; Smith et al. 2005, 2008, 2012; Vogel et al. 2008). It appears that both diet and phylogeny influence enamel thickness. Martin (1985) found thick enamel in the orangutans and thought that it retained the primitive ancestral condition of thick enamel, stressing the importance of phylogeny on the expression of enamel thickness. Andrews and Martin (1991) and Kay (1981) established that primate species adapted to varied diets have thick enamel, while folivorous primates such as the colobines have thin enamel (Shellis and Hiiemae 1986). Martin et al. (2003) examined enamel thickness in hard -seed feeders in various New World primates and found that some hard-seed feeders (sakiuakari) had thin enamel although other hardseed feeders (capuchins) had thick enamel. Vogel et al. (2008) studied the enamel thickness of the molar teeth in the orangutan in comparison with the common chimpanzee and found that the types of foodback foods consumed during the time of food scarcity act as a strong selective force on enamel thickness (ecological hypothesis) while Smith et al. (2012), who compared Bornean and Sumatran orangutans, found limited support for the ecological hypothesis, although they reported that thinner enamel in males than females. Moreover, examining the enamel thickness in modern humans, Macho & Bernier (1993) found that the defined enamel thickness differences occurred from the anterior (M1 being the thinnest) to posterior teeth. A similar trend was found in the chimpanzees (Smith et al. 2008). Thus, the relationship between enamel thickness and diet is not straightforward. Shellis et al. (1998) also noted the effect of body size on the enamel thickness. Phylogeny and some other ecological characteristics may be involved.

The data presented in this research project focuses on the premolar teeth in the guenons (tribe Cercopithecini). The Cercopithecini is the most species-rich tribe within the Old World Monkeys (family Cercopithecidae). The guenons include four genera (Allenopithecus, Cercopithecus, Chlorocebus, Erythrocebus, Miopithecus) that have gone through adaptive radiation in the last 1-2 million years (Tosi et al.

2005). The guenons inhabit the sub-Saharan Africa and primarily feed on fruits and supplement their frugivorous diets either with leaves, insects, seeds, flowers, or others (Chapman et al. 2002). For this reason the differences observed in secondary foods that diverge during the time of food scarcity may play an important role as enamel thickness variation among different guenon species.

Accordingly, this study will test the correlation between several behavioral and ecological factors, and absolute enamel thickness (AET) and relative premolar enamel thickness (RET). In particular, the main hypothesis for this study is that enamel thickness is correlated with diet, and that those species that are frugivoinsectivore or frugivo-semivores have thicker enamel than frugivo-folivores. Another hypothesis to be tested is that enamel thickness increases from the 3rd to 4th premolar teeth within an individual’s maxilla or mandible, and that there will be thickness variation between upper and lower premolars. Lastly I will test whether enamel thickness has any correlation with the maximum altitude of the guenon species' distribution ranges.

Previous studies (Ulhaas et al., 1999; Kato et al., 2004) have established patterns in enamel thickness across primate species that have been applied to studying human evolution and its relation to changes in diet and other factors. This study is especially significant because the guenons are closely related primate species that went through rapid adaptation. Therefore by examining the closely related guenon taxa, determining whether diet or other ecological fac-

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tors have strong effects on the phenotypic expression of enamel thickness is possible. This enables a better understanding of the role of enamel thickness in evolution of not only guenons but also of other species, including humans.

Samples 30 permanent, fully erupted premolar teeth representing eight guenon taxa that have been previously scanned with the use of microcomputed tomography (μCT) system (2010 GE phoenix v|tome|x s240 with the GC Phoenix 3D data acquisition and reconstruction software on HP z800 workstations) by my mentors at the American Museum of Natural History were used in this study (Table 1). Due to the fact that some taxa are more common than others at the museum’s mammalian collection, the sample size for each taxon is unequal. 3D images obtained from μCT scanning were processed using VGstudio Max 2.2 on PCs. Figure 1 shows an example of scanned images of one of the premolars. Some of the teeth of the AMNH specimens are those of old adults that display extensive wears on the teeth. Most scientific studies, as well as this one, use teeth with little decay to avoid results being affected by such abnormalities in tooth structure. Ecological data, dietary data, and body weight on guenon taxa To examine whether RET ad AET relate to maximum ODWLWXGH of the distribution ranges of the taxa used in this study, maximum ODWLWXGe data were obtained by downloading shape files of the distribution map polygons of all the sample taxa from the IUCN Red List (www.iucnredlist.org). Then each shapefile was imported into Google Earth. Using a pin tool, maximum latitude for each taxon’s distribution range was determined. The dietary data were collected from Chapman et al. (2002). All guenons are frugivores. Thus what differs among them is their secondary food source. For this reason, each taxon was categorized as frugivo-semivore (primary food is fruits and secondary food is seeds), frugivo-folivore,

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(primary food is fruits and secondary food is leaves), frugivo-insectivore (primary food is fruits and secondary food is insects), or frugivoTHV feeder (primary food is fruits and secondary food is THV or terrestrial herbaceous vegetation). Body weight data were collected from All The World’s Primates Database (www.alltheworldsprimates.org).

Measurements Measurements of the absolute enamel area (c), enamel-dentine junction (EDJ, noted as e), bicervical diameter (BCD), dentine area (b), and total tooth area of each virtually-sliced premolar tooth section were taken using Fiji (ImageJ)(Rasband, 2014.) on a Wacom Cintiq 13HD tablet connected with an iMac computer (Fig. 2). The software first needed to be calibrated and scaled in mm before measurements.

Linear measurements (EDJ, BCD) were taken from each tooth section and then averaged to obtain a single mean value for each measurement. Area measurements (b, c) were taken using the threshold method. Each measurement was done three times and averaged to take into account any inaccuracies with the equipment and handling. The Wacom tablet system was calibrated often so that all measurements would be correctly overlaying appropriate areas of the tooth. The scale must be checked prior to every measurement, as different 3D images use different scales depending on the size of the tooth.

Using these measurements, average enamel thickness (AET) (mm) and the relative enamel thickness (RET), which is a dimensionless unit, were calculated using the following equations established by Martin (1985) and used by many researchers such as Smith et al. (2005): AET = absolute enamel area (c) / Length of Enameldentine Junction (e) ..... equation 1 RET = [AET x 100]/√dentin area (b) ... equation 2 Statistical analysis To examine whether there are significant differences in RET and AET in relation with the

jaw position, tooth position, sex, Welch’s t-tests were performed. If RET and AET covary with diet, species, body weight, and maximum latitude as confounding variables, Analysis of Variance (ANOVA) was performed. To examine species differences in AET and RET of PM4, general linear models (GLM) were tested for fit. All statistical tests were performed using R studio (v.0.99.441) with R (v.3.2.0). Sample size for the third premolar is much smaller (N= 9) than that of the fourth premolar (N=21). Furthermore there are disparities in sample size among different species. Therefore, I recognize that homogeneity of samples is a problem. Another problem is that small sample size limits the types of statistical analyses that can be performed. Small sample size is a pervasive problem in biological anthropology. Small sample size, especially for PM3, is a caveat of this research. For this reason, the results of this study need to be considered preliminary and they need to be corroborated with further studies involving a much larger dataset.

Results The mean, minimum, and maximum AET and RET and standard deviations of the AET and RET of all the samples used in this study are shown in Table 2. Table 1 also displays the dietary category and maximum latitude of each species. While I hypothesized that males would have a higher average RET, as males are significantly larger in body weight and tooth size, there was not a significant difference between male and female guenon AETs and RETs, perhaps due to small sample size. Body weight had no effect in enamel thickness. The AET and RET of females actually tended to be larger than males (Fig. 3, Fig. 4). Welch t-test result shows that the AET (t= 1.2255, df=27.934, p=0.2306) (Fig. 3) and RET (t = 1.9813, df = 24.574, p =0.05885) (Fig. 4) in regard to sex differences were not significant. AET between left and right sides of the jaws were also not significantly different (L mean= 0.3131445, R mean=0.3466114; t=-0.96913, df = 26.897,

p=0.3411) and RET between left and right sides of the jaws were also not significantly different (L mean= 12.62732, R mean= 13.11699; t =0.33204, df = 23.824, p=0.7428).

The AET (Lower jaw mean = 0.3147635, upper jaw mean = 0.3891016; t = -1.8643, df=9.6744, p = 0.09287)(Fig. 5) and RET (Lower jaw mean =12.75909, Upper jaw mean=13.38355; t=0.42133, df=12.603, p=0.6806) (Fig. 6) of upper jaw vs. lower jaw also had no significance.

However, AET on the fourth premolars (mean= 0.3633 mm, sd=0.099) is significantly thicker than that of the third premolars (mean=0.2593, sd= 0.0499)(t = -3.9725, df =26.199, p<0.001) (Fig. 7). The RET on the fourth premolars (mean= 14.501635, sd= 3.000) is also significantly thicker than that of the third premolars (mean= 9.178856, sd= 3.049)(t=4.4021, df = 14.982, p<0.001) (Fig. 8). Thus, the hypothesis, which states that enamel thickness increases from anterior to posterior in premolar teeth was supported. Nevertheless, as Figures 5 and 6 show, the sample size of PM3 is much smaller than that of PM4. For this reason, this finding must be considered tentative.

I also examined whether there are significant species differences in AET and RET for the combined PM3 and PM4 data. AET shows significant differences (N=30, R2=0.4613, F= 2.691, DF =7 and 22, p= 0.003565) so as RET (N=30, R2=0.4613, F= 2.691, DF =7 and 22, p= 0.003565)(Fig. 9). Furthermore when only PM4 data were analyzed, this relationship also holds for AET (N=21, R2= 0.744, F= 5.397, DF =7 and 13, p= 0.00445) and RET (N=21, R2= 0.6605, F= 3.612, DF =7 and 13, p= 0.02193) (Fig. 10). Analyses on PM3 were not conducted due to limited sample size.

I used the scatter plots of the AET and RET with the maximum latitude of the species range to examine whether general linear model (GLM) apply to these variables. The relationship of the AET-maximum latitude is expressed as y= 0.013x+0.27 (N=30, R2= 0.4271,F=

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20.88, DF =1 and 28, p= 0.0001) (Fig. 11) and the GLM of the RET-maximum latitude of the species range fit was y=0.42x +11 (N=30, R2= 0.24, F= 9.288, DF =1 and 28, p= 0.004991) (Fig. 12).

creases from anterior to posterior teeth (Schwartz 2000). The analysis of the difference in AET and RET between PM3 and PM4 indicated that the enamel thickness increases from PM3 to PM4. A predicted by previous studies, enamel thickness was thicker in PM4 than Then I examined the relationship between diet PM3.. Thus this study’s results support the findand AET and the diet and the RET. Contrary to ing of previous research. This is the first time the prediction, I found no close relationship. that this increase has been confirmed in guenon Figure 13 shows a boxplot of the AET and diets premolar teeth. that shows no statistical significance (N=30, R2= 0.1014, F= 1.053, DF =3 and 28, p= Mackiewicz et al. (2010) studied the relation0.3845). Figure 14 displays a boxplot of the ship between enamel thicknesses of bears RET and diets that also shows no statistical sig- (Oopder Carnivora, family Ursidae, genus Urnificance (N=30, R2= 0.008194, F= 0.07711, sus) compared to other Carnivoran species’ diDF =3 and 28, p= 0.9719). ets and body size. They found that for the molar and premolar teeth within the Carnivorans, the Finally I performed ANOVA on RET to see if thinnest enamel is found in the domestic cat and any variables can predict the RET. Tooth Posi- the thickest in the bears. Generally speaking, tion (PM3 or PM4) (df=1, Sum. Sq.=202.11, the smaller the taxa, the thinner the enamel, and mean Sq.=202.11, F=87.671, p< 0.05) has the the larger the taxa, the thicker the enamel. Howgreatest predictable power followed by Species, ever, there were exceptions; the polar bear Maximum Latitude, Diet, and Jaw (Table 3), (Ursus maritimus), the largest bear analyzed in but the residual of 43.17 indicates that some their study, did not have the thickest enamel. unknown factor must influence enamel thickThey also found that bears with more herbaness. ceous diets had thicker enamel. Generally speaking, this study found that the smaller the taxa, the thinner the enamel, and the larger the Discussion taxa, the thicker the enamel. However, some Enamel thickness has historically been used as a exceptions existed, possibly due to dietary varidistinguishing characteristic in establishing ations as well as evolutionary history. Enamel hominin and hominoid phylogenetic relationthickness does not appear to follow a single ships, with thicker enamel reflecting a more ad- rule, whether that is diet or body size or evoluvanced Homo sapiens-like condition, thereby tionary dietary changes. Enamel thickness is separating hominins from hominoids. Martin’s only one clue to a species’ habits and history.

(1985) research found that enamel thickness increased over time within the hominins and Mangabeys (Genera Cercocebus and Lophocegreat ape clade, but while this thickness has bus) are known to possess thick enamel on their been maintained throughout the evolution of the molar teeth (McGraw et al. 2011). To find out genus Homo, it has secondarily decreased with- how mangabeys have an advantage over the in the African and Asian great apes, but much guenons, Lambert et al. (2004) compared the reduced rate in the orangutans (genus Pongo). hardness of foods consumed by two sympatric Therefore, while humans have extremely thick species, the redtail monkey (Cercopithecus asenamel, it is not necessarily evident that thick canius), which is a guenon species, and the grey enamel would always be found in hominins.

-cheeked mangabey (Lophocebus albigena) living in the Kibale Forest, Uganda. They found It has been known that enamel thickness inthat although much of the year, the mangabey

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and the guenon were feeding on similar fruit foods, during the times of food scarcity the mangabey fed on much harder foods than the redtail monkey. They concluded that the mangabeyâ&#x20AC;&#x2122;s thick enamel helps them to feed on much harder foods that are important fallback foods during crunch times. McGraw et al.

(2011) restudied the thickness in mangabey molar teeth and found that all mangabeys have thick enamel and the reason appears to be their use of seasonal hard foods.

Orangutans (Bornean orangutan: Pongo pygmaeus, Sumatran orangutan: Pongo abelii) also have thick enamel and feed on hard foods, although infrequently. However, P. pygmaeus feeds on more mechanically demanding foods than P. abelii. Yet Smith et al. (2012) found little difference in enamel thickness between these two closely related species. This illustrates the complexity of enamel thickness in the primates.

Ulhaas et al. (1999) compared enamel thickness of the molars in a few species of colobus monkeys in comparison with the guenons. They found that one reason that colobus monkeys had a more even enamel distribution than cercopithecus could be because of colobusâ&#x20AC;&#x2122; feeding system. The reason that the colobus monkeys have thinner enamel than the guenons appears to be because of the folivorous diet.

The above review of enamel thickness studies point that thick enamel would be expected in frugivo-semivorous and frugivo-insectivorous guenons than frugivo-folivorous guenons. However, contrary to this prediction, the hypothesis that the enamel thickness is thicker in those species that feed on hard foods while the species that feed on fruits that supplement their diets with leaves will show thinner enamel turned out not to be correct.

ness and hard-food diet (ecological hypothesis), the guenon data examined in this study did not support this relationship. This may be because of the fact that this study examined only 30 teeth and for each taxon there were only one to nine samples per taxon. Thus this result must be taken with caution.

Kato et al. (2014) reviewed intraspecific and interspecific molar enamel thickness variations among six macaque species, and found that they were similar to hominid molar enamel thickness variations as well. Furthermore, enamel thickness correlated with body mass in some of the macaque species, but could not account for the enamel thicknesses of all of them. Their study also examined the relationship between macrolevel dietary categories and enamel thickness, but they did not find strong correlation. However, the fact that the thick enamel correlates with the maximum latitude indicates that thick enamel evolved in those macaque species that live in more temperate and seasonal habitats. The statistically significant relationship they found between maximum latitude of speciesâ&#x20AC;&#x2122; range and RET is interesting, because this correlation appears to relate to increased seasonality of the habitats. In highly seasonal habitats, animals are often forced to feed on hard foods. They need to become more flexible in switching their diets from high quality soft-fruit dominated foods to more low quality hard-seeds dominated foods, because soft fruits become scarce during the time of food scarcity (Matsuda 2007). Although sample size was limited, this study also found a similar trend that thick enamel was found more in the species that live in higher latitudes than in those species that live in lower latitudes even within the African continent. Therefore finegrained differences in the diet of the guenons that cannot be grasped by gross categorization of diets at macro-level may be an important factor that determines enamel thickness in primates.

Although many studies (Ulhaas et al. 1999, Lambert et al. 2004; Vogel et al. 2008) have In this study, I explored how enamel thickness found close relationships between enamel thick- varies with various ecological variables. I con-

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ducted a number of statistical tests and found a tendency for enamel thickness to increase from anterior to posterior premolar teeth. However, other factors such as sex, body weight, and upper/lower jaw differences had little statistical significance. Furthermore, diet appears to have little effect, although maximum latitude of species range had a predictable value. These results must be taken as preliminary, because this study was limited in scope due to small sample size and also limited opportunities in accessing ÎźCT -scan system. Further studies are needed to corroborate the findings of this study using much larger sample sizes.

Because premolars have not been very well studied in most primate taxa, the data and study results obtained in this study have made a small contribution in understanding the relationship between enamel thickness and several variables.

This study is significant, because it attempted to tease apart whether the effect of diet overrides the effect of phylogeny in the phenotypic expression of enamel thickness in the premolars.

The study results are also applicable in furthering our understanding of the role of enamel thickness in other primate taxa, such as our human ancestral species.

Figure 1. Scanned images of Right Upper PM3 in AMNH 52573 RUPM3. Shown on the left is the image of the mesial bucco-lingually sliced section. The red plus sign indicated the position of the top of the crown at the buccal side, which matched with the red plus sign shown on the same tooth on the right image.

Acknowledgement I would like to thank my advisor Richard Lee of Bronx High School of Science for his guidance and advice and my mother and mentor, Reiko Figure 2. Variables measured to obtain AET and RET Letters correspond to measurements taken of teeth and M. Goodwin of Fordham University who helped me from the beginning to the end of this used in AET and RET computations. research. I also would like to express my sincere thanks to Warren Pardi of Fordham University who ÎźCT-scanned images of the guenon teeth together with RM Goodwin.

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Figure 3. AET between the two sexes. The difference in enamel thickness between two sexes was not significant (t=1.2255, df=27.934, p-value=0.2306, Female mean= 0.3542713, Male mean= 0.3127171).

Figure 4. RET between the two sexes. The difference in enamel thickness between two sexes was not statistically significant (t=1.9813, df=24.574, pvalue=0.05885; Female mean= 14.28660; Male mean=

Figure 5. AET of premolars (both PM3 and PM4 data combines) is significantly different between Upper and lower jaws (N=30, t=-1.8643, df= 9.6744, p=0.09287).

Species: An= Allenopithecus nigroviridiis, Ca= Cercopithecus mona, Cw= Cercopithecus wolfi, Mt= Miopithecus talapoin

Figure 6. RET of premolars (both PM3 and PM4 data combined) is not significantly different between Upper and lower jaws (N=30, t=-1.8643, df=9.6744, p=0.09287). Species keys are found in Fig. 5.

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Figure 7. AET of PM3 is significantly thicker than that of PM3 (N=30, R 2= 0.2625, F=9.965, DF=1, and 28, p=0.00379901). Species keys are found in Fig. 5.

Figure 9. RET of premolars (both PM3 and PM4 data combined) by species (N=30, R2= 0.4613, F=2.691, DF=7 and 22, p=0.003565. Species keys are found in Fig. 5.

Figure 8. RET of PM4 is significantly thicker than that of PM3 (N=30, R 2= 0.4123, F=19.64, DF=1 and 28, p=0.0001308) and species difference. Species keys are found in Fig. 5.

Figure 10. RET of PM$ by species shows significant differences among eight species (N=21, R 2=0.6605, F=3.612, DF=7 and 13, p=0.02193). Species keys are found in Fig. 5.

Figure 11. Statistically significant relationship between maximum latitude of the speciesâ&#x20AC;&#x2122; distribution ranges and AET (N=30, R 2=0.4271, F=20.88, DF=1 and 28, p=0.0001). Species keys are found in Fig. 5.

Figure 12. Statistically significant relationship between maximum latitude of the species, distribution ranges in RET (N=30, R 2= 0.24, F=9.288, DF=1 and 28, p=0.004991). Species keys are found in Fig. 5.

Figure 13. Dietary categories and AET was not statistically significant (N=30, R 2= 0.1014, F=1.053, DF=3 and 28, p= 0.3845). Diet: F-Sem= Frugivo-Semivore; F=Ins= Frugivo-Insectivore; F-Fol= Frugivo-Folivore; F-THV= Frugivo-Terrestrial Herbaceous Vegetation Feeder

Figure 14. Dietary categories and RET was not statistically significant (N=30, R 2= 0.008194, F=0.07711, DF=3 and 28, p= 0.9719). Diet keys are found in Fig. 15.

19

Table 1. The guenon premolars that have been previously ÎźCT scanned, virtually sectioned, and measured for enamel thickness in this study.

Table 2. Mean, Minimum, and Maximum AET and RET of different species and their diet and maximum latitude of distribution ranges

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Table 3. ANOVA table for RET. The large residual indicates that some unknown factors influence the RET.

References 1. Andrews, P., & Martin, L. 1987. Cladistic relationships of extant and fossil hominoids.

Journal of Human Evolution, 16(1), 101118.

2. Chapman C, Chapman LJ, Cords M, Gathua J, Gautier-Hion A, Lambert J. 2002. Variation in the Diets of Cercopithecus Species: Differences within Forests, among Forests, and across Species. In M. E. Glenn & M. Cords (Eds.), The Guenons: Diversity and Adaptation in African Monkeys (pp. 325350). New York: Kluwer Academic/Plenum Publishers.

3. Daegling DJ, McGraw WS, Ungar PS, Pampush JD, Vick AE, Bitty EA. 2011. HardObject Feeding in Sooty Mangabeys (Cercocebus Atys) and Interpretation of Early Hominin Feeding Ecology. PLoS ONE, 6(8), e23095.

4. Dumont, E. (1995). Enamel Thickness and Dietary Adaptation among Extant Primates and Chiropterans. Journal of Mammalogy, 1127-1136.

5. Grine, F., Spencer, M., Demes, B., Smith, H., Strait, D., & Constant, D. 2005. Molar enamel thickness in the Chacma Baboon, Papio ursinus (kerr 1792). American Journal of Physical Anthropology, 812-822.

6. Kay, R. F. 1981. The nut? crackers? a new theory of the adaptations of the Ramapithecinae. American Journal of Physical Anthropology, 55(2), 141-151.

7. Kato, A., Tang, N., Borries, C., Papakyrikos, A. M., Hinde, K., Miller, E., Ku-

nimatsu, Y, Hirasaki, E, Shimizu, D, Smith, T. M. 2014. Intra- and interspecific variation in macaque molar enamel thickness.

American Journal of Physical Anthropology, 155(3), 447-459.

8. Kono RT. 2004. Molar Enamel Thickness and Distribution Patterns in Extant Great Apes and Humans: New Insights Based on a 3-Dimensional Whole Crown Perspective.

Anthropological Science, 112(2), 121-146 9. Lambert JE, Chapman CA, Wrangham RW, Conklin-Brittain NL. 2004. Hardness of Cercopithecine Foods: Implications for the Critical Function of Enamel Thickness in Exploiting Fallback Foods. American Journal of Physical Anthropology, 125(4), 363368.

10. Macho GA, Berner ME.1993. Enamel Thickness of Human Maxillary Molars Reconsidered. American Journal of Physical Anthropology, 92(2), 189-200.

11. Macho, G. A., Thackeray, J. F. 1992. Computed tomography and enamel thickness of maxillary molars of Plio-Pleistocene hominids from Sterkfontein, Swartkrans, and Kromdraai (South Africa): An exploratory study. American Journal of Physical Anthropology, 89(2), 133-143.

12. Martin, L. 1985. Significance of enamel thickness in hominoid evolution. Nature, 314(6008), 260-263.

13.

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13. .Mackiewicz, P., Wiszniowska, T., Olejnic zak, A. J., Stefaniak, K., Socha, P., & Nadachowski, A. 2010. Analysis of dental enamel thickness in bears with special attention to Ursus spelaeus and U. wenzensis (= minimus) in comparison to selected representatives of mammals.

Morphology and Systematics of Fossil Vertebrates. DN Publisher, WrocĹ&#x201A;aw, 60-77.

14. Matsuda R. 2006. Feeding ecology of the mona monkey (Cercopithecus mona) in a seasonally dry flooded forest in the Da homey Gap. Int. J. Primatol. 27 (Suppl 1).

Pgs: Abst #237.

15. McGraw, W., Pampush, J., & Daegling, D. 2011. Enamel thickness and durophagy in mangabeys revisited. American Journal of Physical Anthropology, 326-333.

16. Olejniczak AJ. 2006. Micro-Computed Tomography of Primate Molars. Ph.D. thesis. State University of New York at Stony Brook, United States, New York.

17. Schwartz, G. 2000. Taxonomic and functional aspects of the patterning of enamel thickness distribution in extant large -bodied hominoids. American Journal of Physical Anthropology, 221-244.

18. Shellis, R., & Hiiemae, K. 1986.

Distribution of enamel on the incisors of old world monkeys. American Journal of Physical Anthropology, 103-113.

19. Shellis RP, Beynon AD, Reid DJ, Hiiemae KM. 1998. Variations in Molar Enamel Thickness among Primates. Journal of Human Evolution, 35(4â&#x20AC;&#x201C;5), 507-522.

20. Smith, T., Olejniczak, A., Martin, L., & Reid, D. 2005. Variation in hominoid molar enamel thickness. Journal of Human Evolution, 575-592.

21. Smith, T., Kupczik, K., Machanda, Z., Skinner, M., & Zermeno, J. 2012. Enamel thickness in Bornean and Sumatran orangutan dentitions. American Journal of Physical Anthropology, 417-426.

22. Smith, T., Olejniczak, A., Reh, S., Reid, D., & Hublin, J. 2008. Brief communication: Enamel thickness trends in the dental arcade

22

of humans and chimpanzees. American Journal of Physical Anthropology, 237-241.

23. Spoor, C. F., Zonneveld, F. W., Macho, G. A. 1993. Linear measurements of cortical bone and dental enamel by computed tomography: Applications and problems.

American Journal of Physical Anthropology, 91(4), 469-484.

24. Tosi A, Detwiler K, Disotell T. 2005. XChromosomal Window into the Evolution ary History of the Guenons (Primates: Cercopithecini). Mol Phylogenet Evol, 36 (1), 58 - 66.

25. Ulhaas, L., Henke, W., & Rothe, H. 1999.

Variation in molar enamel thickness of the genera Cercopithecus and Colobus.

Anthropologie, 37(3), 265-271.

26. Rasband, W.S., 1997-2014. ImageJ, U. S. National Institutes of Health, Bethesda, Maryland, USA, http://imagej.nih.gov/ij/.

27. Vogel ER, van Woerden JT, Lucas PW, Utami Atmoko SS, van Schaik CP, Dominy NJ. 2008. Functional Ecology and Evolution of Hominoid Molar Enamel Thickness: Pantroglodytes Schweinfurthii and Pongo pygmaeus Wurmbii. Journal of Human Evolution, 55(1), 60-74.

ARTICLE

How Our Genetic Technology Can Alter the Face of Evolution

By Yi Chen ’16 and Ginger Lau ’19

our growing population. When we look at the evolution of corn, for example, we see remarkable manipulation of the plant’s characteristics from its original ancestors. About nine thousand years ago, a small Mexican grass produced a mere six to twelve edible kernel per year, wrapped in a hard shell underwent extensive selection through human intervention. By the 19th century, over the course of 9,000 years, the modern product known as the maize is 30 cm in length, fifteen times the size of teosinte, easily accommodating 20 or more rows of kernels, all of which are easily accessible and digestible due to the considerably thinner glume (Dorweiler, 1993).

The bright yellow kernels of the juicy, succulent treat we now know today first originated from the skinny ears of a dozen stone hard casings of a Mexican grass called teosinte. How did we achieve such mouthwatering crop from this nearly inedible grass? Through years and years of selective breeding for sweeter and larger kernels. Without much understanding of the alleles, genes and DNA, humans were able to alter the gene pool to an extent as drastic as we see with the teosinte and the corn we know today. (Dorweiler et al., 1993)

In some respects, humans were genetic engineers long before Gregor Mendel’s pea plant experiments that first established the idea of genetics. In its simplest terms, genetic engineering is the manipulation of an organism’s genome to express more favorable traits. With the inception of agriculture during the Neolithic However, with the advent of modern genetics, our genetic technology has extended long and revolution in 10,000 BCE, we see clear selecfar. After the discovery of the structure of DNA tion of better, sweeter tasting crops to sustain

Teosinte versus maize. (A-B) The The female (left) and male (flowers) of teosinte (A) and maize (B). (C) Teosinte kernel (left) and maize kernel (right).

(D) A comparison of teosinte on the left, maize on the right and the F1 of maize and teosinte in the middle. Image credits: (D) John Doebley, Department of Genetics, University of Wisconsin–Madison; all other images, Sarah Hake. (CC BY 4.0)

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by Watson and Crick in 1953, new genetic technology has grown exponentially. From the 1930s to 2000s, scientists used x-rays as a tool to alter genomes. Seeds and insect eggs were pelted with x-rays, inducing random mutations across the genomes (Ahloowali, 2004). Any organism that demonstrated favorable traits were grown and bred. In 2002, methods of genome modifications became less risky and random through techniques using zinc finger nucleases that could delete or replace specific genes and TALENS that could be engineered to cut specific DNA sequences (Carlson, 2012).

Nonetheless, despite how far we’ve come, many restrictions in our current genome editing technology still remain. These procedures are expensive, complex, and could only be used in organisms that were well understood model organisms such as mice and fruit flies. Genetic engineers continued to develop more efficient and versatile techniques.

ria that the company uses to make yogurt and cheese. With further research, they saw that the segments served an important role in the bacteria's immune defense against phages, which are viruses that attack bacteria. If a phage infected a microbe that had a Crispr spacer that identified the foreign genetic element of the phage, then the microbe could recognize the foreign phage and fight back using Cas endonuclease (Barrangou, 2007).

What was most interesting about the Crispr-Cas complex was that it showed an extraordinary specificity in its ability to identify viral DNA sequences and cut them like a precise microscopic scalpel. This ability suggested great potential in genome editing - a specific DNA sequence can be targeted, cut, and perhaps another desired sequence can inserted. A team of researchers lead by Jennifer Doudna and Emmanuelle Charpentier had independently been exploring CRISPR-associated proteins to learn how bacteria use spacers in their immune defenses. Their research tore apart the mechanism behind Crispr-Cas9 complex and have been manipulating it using a complementary RNA sequence, known as “guide RNA” that could be programmed to cut any DNA sequence, not just the viral DNA traditionally used by microbes (Jinek, 2012). When Crispr-Cas9 technology was tested for genome editing, in comparison to TALENs and zinc-finger nucleases, it was like “trading in rusty scissors for a computercontrolled laser cutter”. This technique for genome editing was elegant and cheap - even a beginner in science could use it (Maxmen, 2015).

Recent research on a novel molecular complex known as Crispr-Cas9, can potentially alter phenotypic traits of any organism with great efficiency and minimal complications. Crispr is an acronym for “clustered regularly interspaced short palindromic repeats” and Cas9 is an RNA guided endonuclease that selectively cleaves DNA sequences. Interestingly, the use of Crispr Cas9 in genome editing began not from genetic engineering itself, but from basic research intended to understand the origin of life by sequencing the genome of ancient microbes known as Archaea. Microbiologists noticed a distinct characteristic of sequenced Archaea genomes - there were recurring palindromic segments. Initially, researchers didn’t know what these sequences did, but they knew it was a This powerful tool provides us the ability to do weird characteristic and named it Crispr. (Jinek precisely what selective breeding has allowed et al., 2012) us to do in the matter of a few years. This four year old technique has already been used in In 2005, in the unusual setting at a Danish food many applications of biology. Agronomists company called Danisco, a group of microbiol- have used it to engineer wheat, a staple crop ogists identified the function of these Crispr se- that is the most important food grain source for quences. They identified the palindromic sehumans, to make it resistant to fungi. Medical quences. Streptococcus thermophilus, the bacte- researchers have used it to reverse mutations

24

causing blindness, made cells impervious to HIV, and prevented cancer cell growth. Biotechnology companies have risen exponentially for pharmaceutical and agricultural applications (Maxmen, 2015).

DA, Horvath P. CRISPR provides acquired resistance against viruses in prokaryotes.

Science 315:1709–1712 (2007).

However, as referenced in many superhero movies, “great power comes with great responsibility” and Crispr is no exception to this statement. Questions regarding the implication of this power and the bioethics behind its implementation now arises. Could Crispr Cas9 give us the power to change the course of evolution among entire species? What restrictions and precautionary measures must be implemented to prevent us from tipping the natural balance of our ecosystem?

In the interview, we spoke to Dr. Kevin Esvelt, an evolutionary engineer at the Wyss Institute at Harvard Medical School, who developed significant genetic technologies utilizing the RNAguided CRISPR/Cas9 nuclease that can potentially allow us to alter the traits of entire wild populations.

References 1. Dorweiler, J., Stec, A., Kermicle, J. & Doebley, J. Teosinte glume architecture 1: A Genetic Locus Controlling a Key Step in Maize Evolution. Science 262, 233-235 (1993).

2. Ahloowali, B.S. Global impact of mutationderived varieties. Euphytica 135: 187–204 (2004).

3. Carlson DF, Fahrenkrug SC, Hackett PB. Targeting DNA With Fingers and TALENs. Molecular therapy Nucleic acids (2012).

4. Jinek M, Chylinski K, Fonfara I, Hauer M, Doudna JA, Charpentier E. "A programmable dual-RNA-guided DNA endonuclease in adaptive bacterial immunity". Science 337 (6096): 816–21 (2012) 5. Maxmen, A. The Genesis Engine. (http:// www.wired.com/2015/07/crispr-dna-editing -2/) 6. Barrangou R, Fremaux C, Deveau H, Richards M, Boyaval P, Moineau S, Romero

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declines in infectious diseases since the invention of sanitary techniques (Figure 1) - interestingly, recent trends in diseases epidemiology has shown a simultaneous increase in the prevalence of autoimmune disorders - disorders in which the body’s own immune system attacks its own healthy cells. There seems to be a negative correlation between infectious diseases and

ARTICLE

Are We Too Clean?

autoimmune diseases (Figure 1). (Bach JF, 2002).

An Unexpected Result of the Evolution of

In the last half-century, autoimmune disease has risen sharply in first world countries (Figure 1B). According to the CDC, one in thirteen Americans has a debilitating autoimmune disease. Although these diseases such as Type 1 diabetes and celiac diseases are linked with specific gene polymorphisms, the prevalence of

By Yi Chen ’17 and Ginger Lau ’19 these diseases have increased so quickly - in the matter of a few generations - that researchers A little dirt never hurt. In today’s health have come to hypothesize that there is a compoconscious, sanitary world of antibacterial soaps, nent beyond the human gene pool in play. spray on disinfectants, and modern pasteuriza- (Fairweather D. & Rose N.R., 2004) Counterintion techniques, dirt and disease causing patho- tuitively, that other component contributing to the increase in cases of autoimmunity is pregens are tightly controlled. While enforcing cisely our “clean environment”. (Bach JF, germ prevention habits have prevent the spread 2002). of disease and infections - we have seen sharp

Disease

Figure 1. Inverse Relation between the Incidence of Prototypical Infectious Diseases (Panel A) and the Incidence of Immune Disorders (Panel B) from 1950 to 2000. In Panel A, data concerning incidence of infectious diseases are decreasing. In Panel B, data concerning incidence of Immune Disorders show an increase as years progress.(Bach JF, 2002)

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Figure 2. The Effects of Environmental Factors On Non-allergic and Allergic disorders. The diagram presents how different environmental stimuli influence the determination of the expression of either allergic or nonallergic genes. The recent increase in prevalence of autoimmune disorders, in particular allergies and asthma, is believed to be a result of modernizations of the environment. (Wills-Karp M., Santeliz J., et al., 2001)

Autoimmune disorders are one of the most prevalent disorders worldwide. In fact, it is estimated that autoimmune diseases affects 5-10% of the world’s population. (AARDA, 2010) The recent increases in allergy prevalence have thought to be primarily due to changes in environment as a result of never ending modern advances. The alarming presence of autoimmune disorders worldwide did not come about out of

sheer coincidence. Further investigation of this phenomenon have caused scientists to formulate an explanation known as the “hygiene hypothesis”.

The ‘hygiene hypothesis’ as originally formulated by Strachan, proposes that a cause of the recent rapid rise in atopic disorders could be a lower incidence of infection in early child-

Figure 3. Inverse Relationship between Autoimmune Disorder Incidence and Helminths Infestation Incidence. On the image to the right, parts of North America and Europe are recognized as areas with greater incidence of autoimmune disorders. On the image to the right, South America, Africa, and Asia are recognized as areas with high incidence of helminthic infestation. (Strosberg S.A. & Anthony Stallins J., 2014)

27

transmitted by unhygienic contact with older 86187622.html siblings. (Strachan DP, 1989) Figure 2 presents a diagram representing the differences of non- 2. Bach JF (2002, Sept 19). The Effect of Inallergic and allergic disorders based on environfections on Susceptibility to Autoimmune mental factors. The figure implies that greater and Allergic Diseases. Retrieved from the exposure to environmental stimuli, the more http://www.fortressbiotech.com/pdfs/bach% likely the persons non-allergenic genes are ex20nejm%202002.pdf) pressed, based on recent studies that have the role of genetics on the onset of asthma and al3. Fairweather D., Rose N.R. (2004, Nov. 11). lergies.

Women and Autoimmune Diseases. Retrieved from https://wwwnc.cdc.gov/eid/ According to the hygiene hypothesis, the expoarticle/10/11/04-0367_article sure to infectious agents is required to educate our immune system and prevent us from devel- 4. Strachan DP (1989, Nov. 18). Hay Fever, oping immune disorders. Evidence of this is Hygiene, and Household Size. Retrieved seen through the decrease in infectious diseases, from https://www.ncbi.nlm.nih.gov/pmc/ but increase in immune disorders, as can be notarticles/PMC1838109/ ed in Figure 2. Perhaps the prevalence of immune disorders results from us being too clean. 5. Strosberg S.A., Anthony Stallins J. (2014) (Strachan DP, 1989).

The Humanâ&#x20AC;&#x201C;hookworm Assemblage: Contingency And The Practice Of Helminthic With the assertion of the hygiene hyTherapy. Retrieved from http:// pothesis, there has been significant developuknowledge.uky.edu/cgi/viewcontent.cgi? ment of various new forms of treatment includarticle=1028&context=geography_etds ing helminthic therapy, in which patients with immune disorders intentionally ingest pig worm 6. Wills-Karp M., Santeliz J., Karp CL. (2001, eggs or infect themselves with roundworms to Oct. 1). The Germless Theory of Allergic "train" their immune systems. Although helminDisease: Revisiting the Hygiene Hypothesis. thic therapy is still at its experimental stages, Retrived from https:// many studies have suggested that this therapy www.ncbi.nlm.nih.gov/pubmed/11905816). significantly improves patient conditions.

Would you undergo helminthic therapy if you had a severe immune disorder? (Strosberg S.A. & Anthony Stallins J., 2014).

References: 1. American Autoimmune Related Diseases Association(AARDA) (2010, Mar. 03).

Comprehensive Report on the Global State of Autoimmune Diseases Released for National Autoimmune Disease Awareness Month. Retrieved from http:// www.prnewswire.com/news-releases/ comprehensive-report-on-the-global-state-of -autoimmune-diseases-released-for-national -autoimmune-disease-awareness-month-

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Compiled by Yan Zhang '16

SPECIAL FEATURE

THE YEAR IN BIOLOGY

The Journal of Biologyâ&#x20AC;&#x2122;s choice of the top 25 headlines in Biology for the year 2015.*

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6

Irreproducibility, when experimental results cannot be reproduced, is a major problem in biological and psychological research. Studies found that only 35 of 97 psychology experiments published in three major scientific journals could be replicated, and that $28 billion is spent annually on non reproducible research in the United States alone.

Some researchers posit that factors such as pressure to publish, data omission and bias, faulty statistics, and contamination of specimens contributes to this phenomenon. The Science Exchange and the Center for Open Science, among other groups, are investigating methods of pinpointing the root causes of irreproducibility, especially in cancer studies.

1

Images of Pluto from the spacecraft New Horizons, that traveled 9.5 years to get there, show mountains, ice flows, as well as blue skies! The surrounding 5 moons revealed even more surprises, as Charon has an unique dark polar cap, and the other 4 moons spin.

5

Errors have recently been found in past data relating to the alleged pause in global warming trends between 1998 and 2012. Correcting for these biases from the Arctic, researchers found that the Earthâ&#x20AC;&#x2122;s average surface temperature increased by 0.116 degrees Celsius per decade from 2000 to 2014. Scientists now predict that the Arctic will have its first ice-free winter in 2052, 10 years sooner than earlier predictions.

With more forests, the CO 2 levels will rise along with global temperatures.

2

CRISPR is a basic immune system in bacteria containing RNA and an enzyme that cuts the DNA of invading viruses. CRISPR can be used to edit genes, and is a promising method to treat diseases. However, its use in editing the genes of embryos is highly controversial.

3

New bones of the genus Homo were recently found in a cave in South Africa. The legs and feet bones had characteristics of upright walking, but the shoulders and upper portion of the body were better for climbing trees. Their brains were no larger than those belonging to 2 million to 4 million year old hominids from the genus Australopithecus.

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4

People grow and age at different rates.

Duke University researchers have discovered that some 38 year olds were biologically older and others younger. The suspected causes of the mysterious aging differences between humans lies in damage to brain proteins, loosening of DNA packaging, and greater permeability of the blood brain barrier.

7

NASA’s Cassini spacecraft exploration of Saturn’s moon, Enceladus reveals evidence for buried oceans that could be a place for extraterrestrial life. Most of Enceladus is 200 o C. The Cassini probe found tiny silica particles in one of Saturn’s rings, which were likely formed from high temperatures of 90 o C on geysers on the bottom of the ocean.

12

Recent studies show that a protein related to Alzheimer’s disease called amyloid-beta can rarely act as a prion, causing proteins to misfold. A study in eight postmortem brain of patients with Creutzfeldt-Jakob disease (a prion disease) that had been given injections of human growth hormone contaminated with CreutzfeldtJakob disease show that 4 of the brains had amyloid beta proteins associated with Alzheimer’s disease. This could mean that prions may be a cause of Alzheimer’s disease, but more research is needed.

8

A new phylum of microbes has been discovered by researchers called Lokiarchaeota while examining DNA found in soil sediment.

The new phylum has been observed to share genes similar to those in modern eukaryotes, as well as genes from the domain archaea, that allowed it to ingest another microbe. No actual cell has been identified yet.

9

Experiments on quantum mechanics revealed that the locality principle is violated. The locality principle states that “events separated in spacetime must be independent.”

This year, European researchers studied electrons on opposite sides of a campus, 1.3 kilometers apart, and found locality violation, similar to Bell tests conducted earlier.

11

Superconductor experiments by German researchers involving crushing a compound of hydrogen and sulfur with more than one million times Earth’s standard atmosphere pressure, transmitted electric current without resistance at 203 o K (70 o C). This is higher than the previous temperature of 164 o K. Similar compounds will be tested to see if a higher temperature can be reached.

10

The Roadmap Epigenetics Project has been recently turned into a 3-D movie adaptation.

This movie mainly focuses on how chemical modifications move static DNA and how these modifications turn genes on and off. The researchers say these epigenetic marks, that are either chemical modifications of DNA or histones, take place in more than 100 types of cells. A 3-D perspective had a lot of researchers making new discoveries.

31

13

NASAâ&#x20AC;&#x2122;s Reconnaissance Orbiter spacecraft found hydrated salt particles on Mars. Water has been reported before, however the salt finding is the most specific evidence found to date and provides more evidence for life on Mars.

14

Geologists in New Zealand set off dynamic blasts over 2 nights trying to get a clear look at the underside of the Pacific plate to see how it moves.

A 100 kilometer by 10 kilometer partially melted rock layer, located between the plate and the mantle, assists the motion of the Pacific plate by lubricating it.

15

Cancer genetics of tumors have led to more personalized cancer treatments. Researchers in the U.S. have found that overinterpretation of these genes can be an issue.

For example, Victor Velculescu of John Hopkins School of Medicine discovered that two thirds of mutations in tumors showed up in normal healthy cells in that patient, too.

16

Quarks, one of the fundamental units of matter, are known to be found in pairs or groups of three. Pentaquarks, a clump of 5 quarks, were discovered by researchers at the Large Hadron Collider near Geneva while studying the decay of another particle. This discovery is helpful in understanding the force that holds atomic nuclei together.

32

18

Artificial light has been shown to be a problem for wild animals as many of their mating and reproduction cycles are disrupted. Many wallabies mate a month later than usual, and this causes new mothers to miss the important month for birth when plants are still alive and full of nutrition.

17

Edvard and May-Britt Moser from the Norwegian University of Science and Technology earned a Nobel prize for discovering special mental navigators labeled as grid cells that can direct a mammal in space using information on how fast the mammal is moving (speed cells). Since similar cells are found in all mammals, these cells may also be found in humans.

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Researchers have new research

on gene-editing, more specifically on a biological process called Clustered regularly interspaced short palindromic repeats (CRISPR). Using CRISPR single celled organisms would recognize it as a invader hence activating proteins to tear the DNA apart. They were also concerned about how accurate the CRISPR could activate the proteins to cut out specific unwanted parts of the genes. They also wanted to

insert a favored gene in place of the cut up unwanted gene. Rodolphe Barrangou had discovered about CRISPR

24

H7N9 influenza began somewhere in Mongolia or the Korean peninsula. The migration patterns of the birds allowed multiple influenza strains to swap pieces of genetic code and H7N9 was born. The H7N9 then hitched a ride onto the poultry markets of eastern China and

by February it leapt onto humans. Most people reported to have H7N9 have had some kind of contact with poultry.

s immune function that did exactly what researchers were searching for.

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20

Bioengineer Jay Keasling from the University of California, Berkeley developed a way to make largescale changes to the metabolic pathways of yeast to create artemisinic acid, which can be converted to aremisinin. This is important because a malarial vaccine depends on artemisinin, a derivative of the sweet wormwood plant, that can sometimes be in short supply.

MacArthur Foun-

dation â&#x20AC;&#x153;Geniusâ&#x20AC;? fellowship winner Sara Seager from MIT is interested in studying the existence of exoplanets. Recent evidence show that many planets have environments suitable for habitation. The Transiting Exoplanet Survey Satellite (TESS) set to launch in 2017 will do an all-sky survey searching for rocky planets around common bright red dwarfs that are smaller than the sun.

21

The U.S. holds top spot in world natural gas and petroleum production, toppling Russia's reign over the industry. The secret behind the United States success is fracking, a method that punctures the ground in search for oil reserves.

22

Malaria still prevails as one of the most dangerous parasitic diseases, with over half of the world at risk. Fortunately, scientists have created a new vaccine made from the sweet Wormwood plant that provides 100% protection against the parasite. The only downfall to this vaccine is the price, starting at $1,100/kg due to the timeconsuming procedure to process the plant.

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ARTICLE

Into the Far Future By: Ashley Loke ‘18 and Angie Yang ‘19

According to the United States Census Bureau’s American Community Survey (ACS), 15% of all new marriages in 2010 were interracial. This percentage is expected to increase steadily over the years. (Wang, 2012). As interracial marriages become more common, scientists believe that future humans will have a combination of features common to different ethnicities.(Cheney-Rice, 2014). Eventually, everyone will be have the same race. This is known as monoethnicity. (Funderburg, 2013).

After this turning point in the evolutionary history of mankind, several issues that have arisen from diversity such as racism might no longer an issue. However, individuals will lose their distinct cultural characteristics. (Olson, 2013).

The effect of monoethnicity on humanity’s well -being will be hard to truly understand and is widely debated among scholars.

Along with monoethnicity, our skin color will most likely change. Studies have shown What will humans look like in the future? What physical characteristics will we pos- that lighter colored skin tend to absorb more UV light. In the past, natural selection has fasess? How will we behave? How will we vored lighter skin color over darker skin color, evolve? Would evolution benefit or harm our species? Scientists have tried to predict the fu- especially in northern latitudes where UV light is less abundant. Due to the increased exposure ture of human evolution for decades. In the timeline of history, human primates only occu- to UV light, we will most likely have darker py about 1% of the spectrum. Is it possible that and more pigmented skin. Since the earth’s ozone layer is deteriorating due to human imwe have already reached the peak of human evolution or will we continue to evolve? Most pacts, we can expect more UV light to penetrate through the ozone. Evolution might soon favor of the scientific community agrees that if humans do continue to evolve, we would do so in darker skin colors since darker skin would absorb less harmful UV rays and prevent ailments a technological-oriented way. Another theory that come with increased exposure to the UV lies in off-world migration, which is the idea that humans will someday inhabit other planets rays, such as skin cancer. Humans that live near in distant galaxies. (Owen, 2009). These possi- the equator are more inclined to have darker bilities will constantly boggle our minds. Ulti- skin because they have more exposure to UV mately, we will be able to banish the nebulous rays in contrast to people living in higher latifog of time and see into the far future of human tudes. However, as technology improves, offworld migration becomes more feasible. We evolution.

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may not have to worry about UV light if we can find another planet or star that sustains life and restart there. Unfortunately, we may not always have access to direct sunlight like we do on planet earth. As a result, our eyes will have to become bigger in order to be more efficient in capturing any available light. (Richard, 2013).

In terms of physical stature, scientists are in disagreement about whether humans will grow taller or shorter. Some scientists believe that humans can only grow taller because of an abundance of nutrients. For instance, according to a recent study, adult men in the United Kingdom have grown by 4 inches in the past 100 years. On the other hand, others argue that increased usage of electronics, such as video games, will produce more sleep deprived humans. Less sleep would result in stunted growth. Moreover, adolescents are reaching puberty earlier in their lifetime. In the 1800â&#x20AC;&#x2122;s, the average age of puberty for girls in the US was 17. (Blaszczak-Boxe, 2014). The current age of menarche, the age when girls get their first menstrual period, is 12.8 to 12.9 years old. An early onset of puberty has been linked to an increased chance of obesity, high blood pressure, and type 2 diabetes in adulthood. Since obesity has also been linked to eating too much fatty foods, our digestive system, the method in which our body breaks down food to use for nutrients, will change.

Along with a change in physical stature, our skeletal structures will also change. Humans will get more and more intelligent. It is feasible for our brains to grow larger. (Shapiro, H.L.).

However, with larger foreheads, the likelihood of giving birth via C-sections will increase. This does not pose a major problem because Csections have a higher chance of success nowadays and scientists expect the probability of

success to increase as we head into the future.

Since our skeletal structure is changing, we can expect a major part of our skeleton to change was well. Our teeth are the hardest bones in our body. They are tiny structures covered in a material called enamel. We already know all of these things because we have the evidence right in front of us (or rather, right inside our mouths). Thanks to fossil evidence, we already know how our teeth looked like in the past but how will our descendants' teeth look like in the future? One prediction that scientists have made is that humans will have less teeth .

Each tooth will become smaller and weaker.

This is due to our changing diets. Early humans have eaten a decent amount of starchy foods, such as roots. Nowadays, our food is less pasty.

As time goes on, the burden on our teeth will decline. Thus, the hardness of teeth will decrease since there is no need for them to be as strong as they used to be (Shapiro, 1933). As technology continues to make our lives easier, human teeth will most likely grow weaker and weaker. For the same reason, human teeth will likely evolve to be smaller and less in number.

As it becomes less necessary to use our mastication, or chewing, muscles as vigorously as they have been used in ancient times, these muscles will evolve to be smaller. Due to this, our jaws will become smaller. Smaller jaws implies less room for teeth, which indicates that we will have smaller and less teeth (Wilford, 1988). On a similar note, humans will likely lose their wisdom teeth as they evolve. Wisdom teeth are the hindmost molars that grow after adulthood. They can cause severe pain when they rupture. Our ancestors may have used them in some way. In the modern era, wisdom teeth do not help us in any way (Shapiro, 1933). Rather, they can harm us. In fact, 35% of the

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world’s population are already born without their wisdom teeth.

In 2012, the average life expectancy was 70 years old. However, by 2030, life expectancy is expected to be over 85 years old. This sudden increase of longevity can be linked to important breakthroughs in medicine and better sanitary conditions. As a result, death caused by infectious diseases have plunged over the years.

Instead, people are more at risk for autoimmune and degenerative diseases. Unfortunately, scientists predict that our immune system will become more frail because of our augmented reliance on vitamins and medication. Over time, our bodies will lose the ability to produce our own hormones and other important chemicals.

Although this shows that our knowledge in the medical field is expanding, there is a severe drawback to an increased dependence on medicine. In the event that all the world’s vitamin supplements were to be destroyed, every human would perish due to insufficient amounts of nutrients. (Fauen, 2012).

Today, humans spend hundreds of dollars on hair removal products: razors, shaving cream, waxing, you name it! Luckily, humans will most likely lose their body hair over time. Human women will lose their hair before their male counterparts because there is a greater pressure from society for women to get rid of their unwanted body hair. Other things that scientists predict will disappear include our last pinky toes.

What is in store in the future for our feet? Scientists say that humans will likely lose our toes as we evolve. This is not an unusual form of evolution. The loss of toes has been demonstrated as perfectly possible by modern animals such as camels, horses, and pigs. In ancient times, humans needed toes to climb and

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hold onto tree branches. However, when humans evolved to become bipedal, the ability to walk on two legs, these toes that were previously used to grapple now had less of a purpose.

That is why human toes are small and stubby.

As humans evolve, they may go as far as to even lose their fifth and smallest toe, their pinky toe. The first toe’s importance is demonstrated by its size. Similarly, the smallest toe is the least important. (Fauen, 2012). For some people, the pinky toe is so small that it doesn’t even have a toenail. Although the evolution process is very slow and the toe may begin disappearing by just shrinking.

The course of evolution stretches back millions of years. As with all things, we will continue to change. Yet, the exact changes that will take place are still ambiguous because scientists can only make an inference. For now, science is the only way for us to delve deeper into the realms of the far future.

References: 1. Admin. “The Past and Future of Human Brain Evolution: Are You Ready for the Release of the Amygdala?” Mind the Brain. 18 November 2012.

2. Blaszczak-Boxe, Agata. “Taller, Fatter, Older: How Humans Have Changed in 100 Years.”

Livescience. 21 July 2014.

3. Cheney-Rice, Zak. “National Geographic Determined What Americans Will Look Like in 2050, And it’s Beautiful.” News Mic. 10 A pril 2014.

4. Fauen, Eva. “Top 10 Possible Next Steps in Human Evolution.” Listverse. 12 November 2012.

5. Funderburg, Lisa. “The Changing Face of America.” National Geographic. October 2013.

Macrae, Fiona. “Humans Could Develop Beaks Like Pufferfish Because Our Teeth are ‘No Longer Fit For Purpose,’ Claims Scientist.”

Daily Mail. 3 July 2013.

6. Nosowitz, Dan. “Humans May Evolve To Grow an Endless Supply of Teeth.” Popular Science. 12 July 2013.

7. Olson, Parmy. “How the Human Face Might Look in 100,000 Years.” Forbes. 7 June 2013.

8. Owen, James. “Future Humans: Four Ways We May, Or May Not, Evolve.” National Geographic News. 24 November 2009.

9. Shapiro, H.R. “Man-500,000 Years From Now.” Natural History. December 1933.

Sjogren, Kristian. “What Will We Look Like in a Million Years?” Science Nordic. 14 January 2012.

10. Richard, Michael Graham. “What will Humans Look Like in 100,000 Years?” Mother Nature Network. 23 July 2013.

11. Wang, Wendy. “The Rise of Intermarriage.”

Pew Research Center. 16 February 2012.

12. Wilford, John Noble. “Human Teeth, Small Already, Keep on Shrinking.” The New Y ork Times. 30 August 1988.

13. Zolfagherifard, Ellie. “Are We Evolving into a New Type of Human? ‘Different’ Species Will Have Evolved By 2050, Scientist Claims.”

Daily Mail. 11 September 2014.

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long period of time, there is no way to physically see the speciation start and finish in our lifetimes. (Morell, 2013).

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Scientists believe that there is currently speciation between different types of killer whales in the Atlantic ocean because two different groups with different dietary needs have developed. Orcas naturally travel in pods, which are usually small groups that hunt and travel together. By examining measurements of whales from the past 130 years, it has been found that there are actually two types of pods in the Atlantic Ocean right now, one that consumes fish, and the other that eats mammals.

Although this differentiation in diet may not seem like a big deal now since the orcas still look and behave in similar ways, it is significant

By Crystal Wu â&#x20AC;&#x2DC;16 because the separated reproduction between the two groups may lead to different developments and behaviors. In fact, it has already been obThe speciation of killer whales is a de- served that the whale pods that hunt herring are bated topic since there is no way of proving that large and communicate a lot. However, the pods that hunt seals are smaller and usually silent it is actually happening. Evolution happens over This is due to the differences in prey because an extensive amount of time, requiring genera- seals are sensitive to sound. The differences in tions to pass before significant changes are behavior can be tracked by not only their location and movement differences, but also by seen. Evolution occurs when traits are passed physical differences such as their teeth. This on and changed throughout multiple generacan be seen by the photos of killer whale teeth tions. Speciation is when a species evolves and in Figure 1 (Morell, 2013). develops distinct traits that makes the mating of However, does the behavior difference the two species impossible. This occurs through continuous reproductive isolation, which means that there would be no gene flow between the two populations. Reproductive isolation can be due to differences in habitats, mating seasons, mating behaviors, sex organs, and incompatibility of the egg and sperm. Many speciation occurrences are due to habitat isolation, which makes the speciation of the killer whales such an uncommon and interesting case. The two populations of killer whales that are developing are both located in the Northern Atlantic Sea. Since these traits develop over a course of a Figure 1. Comparison of the whale teeth (Morell, 2013)

Speciation of Killer Whales

prove that speciation is occurring? Although References there is a definite difference in their hunting 1. Morell, V. (2013, August 16). North Atlanhabits, there is little evidence showing that the tic Killer Whales May Be Branching Into whales from the two different pods have physiTwo Species. Retrieved April 19, 2015, ological differences. in fact, when samples of from http://news.sciencemag.org/ whales from fish pods were tested, there were evolution/2013/08/north-atlantic-killerno significant differences from either modern or whales-may-be-branching-two-species ancient whales that consumed mammals. The one difference that some scientists have ob- 2. Saey, T. (2010, May 4). One ocean, four (or served is that the teeth of whales that have a more) killer whale species. Retrieved April diet of predominantly fish are usually worn out 19, 2015, from https:// and damaged (Morell, 2013). The difference www.sciencenews.org/blog/deleted-scenes/ can be seen in figure 1, where the teeth of both one-ocean-four-or-more-killer-whalewhales are displayed. A model of the teeth of species the whales that consume fish are below the teeth of the whales that consume mammals. However, this is not a trait that is limited to the killer whales that eat fish. A mammaleating family pod off the coast of East Greenland was tested and it was found that their teeth were similar to those of fish-pods. Scientists have also tested the different pods on a cellular level. A common way of studying the relationships between multiple types of animals is comparing the genetic material. Biologists have compared the mitochondrial DNA of the two killer whales and determined that they were too similar to be considered different species (Saey, 2010).

However, this does not mean that speciation is not currently occurring. Most scientists believe that the whales are diverging, at a slow pace. Due to their long lives and few reproductive cycles, the killer whales require many years for multiple generations to pass. Throughout the generations, different phenotypes are developed through the population, depending on what mutations occur and which ones are advantageous.

However, the slow changes in the two pods of killer whales support that hundreds, and maybe thousands of years in the future, there will be a divergence in the killer whaleâ&#x20AC;&#x2122;s evolutionary tree.

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react against the stressor. (Chang, 2006) For example, a message can be sent to muscles in the body in order to allow the human to perform beyond their usual performance when they fight or flight. (Altman, 2014) Human Stressors and Responses In the past, stressors were very different when compared to present day stressors. In the Neolithic era, the stress response system was one of the factors that allowed for humans to survive until today because it provided them aid in times of danger. One scenario could be while picking berries or hunting for food, a wild animal suddenly attacks you. The first sight of danger causes your hypothalamus to send a signal to the pituitary gland which sends on to your adrenal gland and finally to the cells that will help you escape this situation. When a stressor

By Olivia Guan ‘17 is present, the human body pumps the heart two to three times faster and sends extra nutrients to What is Stress? your major muscles. Some systems such as the Selye created the term stress and defined digestive system and the immune system is shut it as “the nonspecific response of the body to down and the excretory system is highly active any demand for change.” Stress is an organin order to make it easier for you to to fight or ism’s response to changes to their environment take flight in order to survive this dangerous or is their response to stressors. (The American situation. (Stock, 2008) Institute of Stress, n.d.) Often when a human is stressed, they react with fight or flight meaning their body will either react and fight for survival or flight (leave the area of danger) in order to survive.

Stress and Its Impact on Human Evolution

Mechanisms of Stress Stress is monitored in the human body by the stress response system also known as the hypothalamic-pituitary-adrenal axis. When a stressor or a change in environment is detected, the hypothalamus sends a signal to the pituitary gland which sends the message through the blood to the adrenal glands. As seen in Figure 1, upon receiving the signal, the adrenal glands proceed to secrete cortisol which is a “stress hormone”. These stress hormones bind to receptors and send separate signals to all the cells in the body in order to coordinate a response to

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Figure 1 Production of Cortisol Cycle

son’s health. For optimal performance and health benefits, a relative balance of good stress and distress is necessary. Excessive distress may lead to cardiovascular diseases, constant headaches, binge eating which may lead to other diseases or ultimately, a breakdown. (Nixon P: Practitioner 1979)

Figure 2 Human Function Curve (Nixon P:Practitioner 1979)

However, in this present day, humans are no longer on high alert and on the lookout for predators. Even so, stress has increased into modern-day life. Unlike in the past, where a stressor was only present for a short amount of time, today, stressors are present in the daily lives of people to the point where it is considered natural. Stressors are now often seen in work, time and money management for adults and school work, tests, the pressure of maintaining grades for a good college for teenagers and children. Being stressed can have positive outcomes for a certain amount of time known as “eustress” and allow the person to work most efficiently and effectively during that time.

However, constantly having stressors and being stressed day-in and day-out present negative effects and may actually shorten the lifespan of humans rather than extend it. (The American Institute of Stress, n.d.)

References: 1. Altman A. (July 16, 2014). Why You Are So Stressed About Stress. (5299). New York Times Opinion Pages (OP TALK).

Retrieved January 10, 2015, from http://optalk.blogs.nytimes.com/2014/07/16/whyyou-are-so-stressed-about-stress/?_r=0 2.

Chang, K. (2006). Study, in a First, Explains Evolution's Molecular Advance. Retrieved January/February, 2015, from http:// www.nytimes.com/2006/04/07/ science/07evolve.html

3.

Nixon P: Practitioner 1979

4.

Stock, J. T. (n.d.). Are humans still evolving?: Technological advances and unique biological characteristics allow us to adapt to environmental stress. Has this stopped genetic evolution? Retrieved November 10, 2015, from http://www.ncbi.nlm.nih.gov/ pmc/articles/PMC3327538/

5.

The American Institute of Stress. What is Stress? (n.d.). Retrieved February/March, 2016, from http://www.stress.org/what-isstress/

Effects of Long term Stress Long term stress may lead to many diseases and illnesses and shorten life span rather than lengthening it. Being around stressors constantly causes the stress response system to be on when it is designed only to be used in lifethreatening situations. As seen in Figure 2, the Human Function Curve, different types of stress yield varying responses and impacts on a per-

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ARTICLE

How Have Humans Evolved From Their

Skull Supported vs. Hanging From the Vertebral Column: Humans have their skull supported on top of a vertebral column while their ancestors

By Sharon Yu ’17 have their skulls hanging from the vertebral colOver time, organisms evolve in order to umn. This was hypothesized to be because of be fit for the environment that they live in. Hu- the size of the human brain compared to the size mans are not excluded from this phenomenon. of the chimpanzee's brain. As stated before, the The following are some features that have human brain evolved to become larger than changed from the non-human primates and hu- their ancestor’s. Since the human brain is larger, mans. it needs more support to remain in place (Smith, Limited vs Dense Hair Coverage: 2012).

Unlike most other mammals on Earth, human do not have a dense coverage of fur or Bipedal vs Quadrupedal Gait: hair. Human ancestors had much more hair covBipedal refers to an organism who erage. Though it is not certain, researchers have walks on two legs while quadrupedal refers to hypothesized on the reason. There are three an organism that walks on all four limbs. This is main hypotheses: (1) a gene for skin color is indirectly related to the shedding of hair since it hypothesized to be because walking on two legs protected the skin from ultraviolet radiation saves energy. In a study at the University of Arwhich meant that hair was no longer needed for izona, it was seen that humans saved more enerprotection; (2) primates with less hair had less gy than chimpanzees when walking on a treadof a problem with external parasites therefore the ones with less hair were more fit for surviv- mill. The amount of energy released was measal; and (3) primates found others with less hair ured through the amount of oxygen released. more attractive therefore natural selection even- Humans saved up to 75% of energy compared tually eliminated body hair (Wade, 2003) to the chimpanzee because we are bipedal (Silverman, 2015).

Larger Brain vs Smaller Brain:

Ancestors?

Human brains are known to be exceptionally larger than those of their ancestors. It is hypothesized that this is because in humans, the

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brain is used more than any muscle in the body.

It is described as “hungry” since it requires the most energy to function. Glucose transporters are found on brain cells which allow the intake of glucose. When there is an insufficient amount, the brain “starves”. The sufficient amount of glucose allows the brain to sustain a larger size than the brains of human ancestors (Smith, 2012). This change in size allows the brain to develop more and become more advanced than the brain of primates. It is the reason why humans can learn languages and actions more quickly than primates can (Sherwood, 2008).

References: 1. Dunn,

R. (2010). The Top Ten Daily Consequences of Having Evolved. Retrieved from http://www.smithsonianmag.com/sciencenature/the-top-ten-daily-consequences-ofhaving-evolved-72743121/?no-ist 2. Sherwood,

C., Subiaul, F., & Zawidki, T. (2008). A natural history of the human mind: tracing evolutionary changes in brain and cognition. Retrieved from http:// www.ncbi.nlm.nih.gov/pmc/articles/ PMC2409100/ 3. Silverman,

J. (2015). W hy do Humans W alk on Two Legs? Retrieved from http:// animals.howstuffworks.com/mammals/ bipedalism.htm 4. Smith,

A. (2012). How did Human Brains Get to be so Big? Retrieved from http:// blogs.scientificamerican.com/guest-blog/howdid-human-brains-get-to-be-so-big/ 5. Wade,

N. (2003). W hy Humans and their Fur Parted Ways. Retrieved from http:// www.nytimes.com/2003/08/19/science/whyhumans-and-their-fur-parted-ways.html? pagewanted=all

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RESEARCH

Abstracts of Student Research

the antipsychotic used, and (2) in addition, we asked whether the patients showed significant Correlates of Treatment Response and Brain differences from controls at baseline, and if so, Abnormalities in First Episode Schizophre- whether we might see normalization of these differences after twelve weeks of treatment. nia Freesurfer software was run again to correct for recorded mistakes. In order for Freesurfer to In the present study we examined a unique render the brain as a 3D image, it must be forgroup of first-episode schizophrenia patients with little or no antipsychotic exposure enrolled matted on a brain atlas. The atlas serves as a template for the gyri and sulci to be labeled and in a double blind 12 week clinical trial of risperidone versus aripiprazole and age- and sex defined. The atlases are based on a pre-installed training brains and geometric points from the -matched healthy volunteers at baseline and cortical model This atlas is used to automatifollowing 12 weeks. We ask: (1) whether cally parcellate the gyri and sulci of the brain. structural characteristics at baseline (in firstFreesurfer was tested in and proven to be valid, episode patients) could predict the degree of improvement after twelve weeks, regardless of reliable, and useful for morphometry studies regarding the surface of the cortex. Data were Mustafa Alvi

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collected and basic T-tests were run to compare thickness and volume averages within groups.

These values would need to be corrected for multiple comparisons. ANOVA (F-test) used to compare independent variables group and time to dependent variables thickness and Pars Orbitalis. The data did not present any statistically significant differences between the two treatment.

PM levels in selected neighborhoods of East Harlem in comparison to that of NYC. BC and PM2.5 concentrations increased up to 9 times and 4.5 times the average concentration count, respectively. This study validates the relationship between sources that contribute to local air pollution and the overall air quality in which the source is located. Currently, there are no standards that regulate the discharge of BC and PM2.5.

Trina Barua Yi Chen Pilot Assessment of Air Quality in East Harlem, New York IL-2 as a Therapeutic Target for Treatment of Autoimmune Alopecia Areata New York City (NYC) has high levels of air pollution, making it the ideal location for an air quality assessment. The 10029 zip code of East Harlem is subjected to extreme amounts of air pollution due to the abundance of polluting sources found in the area. For example, East Harlem is home to six of seven bus depots located in Manhattan. Airborne pollutants emitted from local sources have a significant impact on the health of people who live in this area. The objective of this study was to characterize the air quality of East Harlem and gain an understanding of the significant contributors in the area through the assessment of black carbon (BC) and particulate matter (PM2.5) levels. BC and PM2.5 levels were measured using a MicroAethalometerâ&#x201C;&#x2021; and two AirBeams. The MicroAethalometerâ&#x201C;&#x2021; measures the rate of change of absorption of transmitted light on filter media. The AirBeam uses a light scattering method that is converted into a measurement that estimates the number of particles in the air. This study displays the prevalence of both BC and

Alopecia areata (AA) is a prevalent autoimmune disease caused by T cell mediated destruction of hair follicles. Immune pathways involved in AA are not well understood, restricting development of targeted treatments.

Recent genetic studies in AA performed in our lab have identified mutations in genomic regions of interleukin 2 receptor A (IL- 2RA), implicating IL-2 signaling in AA pathogenesis.

Last year, it was shown that alopecic T effector cells had increased response to IL-2 upon stimulation (p<0.05). In this study, IL-2 was used as a therapeutic target for AA treatment. Interestingly, opposing approaches to IL-2 manipulation - inhibition of IL-2 signaling via Jakinibs and administration of IL-2 via low dose IL-2 therapy â&#x20AC;&#x201C; suggested positive treatment of AA. AA patients who received treatment with FDA approved drug Ruxolitinib, a JAK1/2 inhibitor, demonstrated near full hair regrowth after three months and decreased T effector cell response to IL-2 upon stimulation. When low dose IL-2

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therapy was administered in a mouse model of AA (C3H/HeJ), reduced severity during the onset of the disease was observed. Among PBMCs of low dose IL-2 treated mice, there was a decrease in CD8 and CD4 T cell numbers and an increase in T regulatory cells (Tregs) compared to PBS controls. Taken together, it was concluded that IL-2 plays a crucial role in autoimmunity and is an attractive therapeutic target due to its dichotomous role that can induce both immune activation and tolerance.

This study highlights the pleiotropic nature of cytokines that allows them to be versatile therapeutic targets. Findings from this study may also be applicable to other autoimmune diseases such as Type 1 diabetes, Celiac disease, rheumatoid arthritis, and psoriasis, which also harbor an IL2RA mutation.

Kathryn Chin Dendritic cells in the pancreatic tumor microenvironment are hyper-responsive to TLR2 and Dectin-1 co-ligation

the T cells, which allows the cancer to grow. In this study, I investigated the cytokine expression of dendritic cells through the TLR2 and Dectin-1 receptors in the spleen and tumor microenvironment of tumor bearing and nontumor bearing mice in order to determine how these dendritic cells interpret and interact with their environment. Dendritic cells were isolated from control and cancer mice, stimulated with toll-like receptor 2 (TLR2) and Dectin-1 ligands, and co-cultured with CD4 and CD8 T cells for 36 hours. Cytometric Bead Array revealed that dendritic cells in the pancreatic tumor microenvironment are hyper-responsive to TLR2 and Dectin-1 co-ligation. This study expands the way scientists are able to investigate dendritic cell function, and answers the previously open question of how certain damageassociated molecular patterns (DAMPs) can directly and indirectly influence the anti-tumor response. This is critical because further investigation may lead to new cancer therapeutics involving manipulating endogenous DC. Jenelle Cocorpus

Ranking fourth among cancer-related deaths worldwide, pancreatic ductal adenocarcinoma (PDAC) boasts a dismal prognosis. In cancer, the immune system does not elicit an immune response to the tumor. Dendritic cells, which are part of the immune system, differentiate and activate T cells to fight diseases. The antigenspecific T cells would then proliferate, helping to coordinate the overall immune response against PDAC. However, in cancer, the T cells fail to activate and do not proliferate, allowing tumor progression. Therefore, there must be a miscommunication between dendritic cells and

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Diabetes, Family History of Diabetes and Endometrial Cancer Risk Endometrial cancer is the fourth most common type of cancer in women in the United States and this number is steadily increasing. In many of the past studies, diabetes and obesity were shown to increase the risk of developing endometrial cancer. A family history of diabetes increases the risk of diabetes, but it is unknown whether it could cause an increased risk of developing endometrial cancer. In this study, the

association between family history of diabetes and development of endometrial cancer was investigated. Data on family history of diabetes, demographic, and other medical factors from 469 endometrial cases and 467 healthy controls from the EDGE Study (Estrogen, Diet, Genetics, and Endometrial Cancer) were included in the study. In this study, data from each of the participants were analyzed and compared. Odds ratios and 95% confidence intervals were calculated. Results show an increased endometrial cancer risk for women with a family history of diabetes (odds ratio (OR) = 1.5; 95% confidential interval (CI), 1.0 â&#x20AC;&#x201C; 2.1) after adjusting for the endometrial cancer risk factor variables When it was adjusted the second time with the endometrial cancer risk factor variables and having diabetes, the new adjusted odds ratio was 1.4 (95% CI, 1.0 â&#x20AC;&#x201C; 2.0). Therefore, the study shows that family history of diabetes was associated with an increased risk of endometrial cancer.

was used to map the survey locations, and to calculate the distance from each survey point to development and forest. The proportion of positive sightings increased over time for all species; this relationship was significant for all species. Coyotes were sighted closer to development (R2=0.4306) and farther away from forest (R2=0.4786) over time, and red foxes were being sighted closer to development (R2=0.4434) over time. I conclude that the proportion of sightings for all species is increasing, and that coyotes and red foxes are being sighted closer to developed land over time.

Lauren De La Ossa Chemical compounds did not rescue the developmental consequences of Raf mutation in Drosophila melanogaster, which models a Noonan syndrome mutation

Noonan syndrome is a genetic disorder that affects around one in every 1000-2500 births. Its Ben Davar effects include developmental disorders and cardiac defects. There is currently no known Estimating Predator Distribution Over Time cure for the disease, but efforts are being made and in Relation to Suburban Development to find a potential cure. The genome of Drowith Citizen Science Data sophila melanogaster, the fruit fly, can be given mutations that cause similar developmental deThe purpose of this study was to find where 3 fects in flies as those in humans with Noonan species of predators, bobcats (Lynx rufus), coy- syndrome, including Raf mutations, which otes (Canis latrans), and red foxes (Vulpes vul- cause flies to die in the pupa stage of developpes), were being seen in southern New York ment, right before they hatch. In this experiand Connecticut, and how patterns of observa- ment, Drosophila were given a Raf mutation, tion have changed over time. Survey data from which is one of the mutations found in Noonan 2012 to 2014 were used, citizen scientists resyndrome. Eighteen different non-FDA apported whether they had seen any of the target proved chemical compounds were tested on species on their property. A geocoding program these mutated flies as potential cures for the dis-

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ease. Raf mutated fly embryos were exposed to these compounds at 3 different concentrations per compound. The compounds tested did not rescue the flies, since the flies did not develop past the pupa stage. However, there was a significant difference in the number of pupae in some of the vials compared to the control group.

better exercise, eating, smoking, and drinking habits, which factor into their high rate of their quality of life. As the number of patients with cancer continues to increase worldwide, improving self-care in this population takes on added importance.

Amira Farid

Analysis of fecal calprotectin as an inflammatory biomarker for post-surgery Crohn's disease patients

A Mixed Methods Study Analyzing the Effect if Self-Care Practices on the Quality of Life of Patients with Multiple Comorbidities

Eve Frangopoulos

Background: Most patients with Crohnâ&#x20AC;&#x2122;s disease (CD) will require one or more operations Approximately 1,658,370 new cancer cases are in their lifetime. However, surgery is not a cure expected to be diagnosed in 2015 in the United and postoperative CD recurrence is extremely States alone, and about 589,430 Americans are common. The current method for post-operative expected to die of cancer. People with multiple monitoring is macroscopic, however early signs comorbid diseases, namely cancer, type 2 dia- of inflammation in CD patients is microscopic. betes (T2D), and cardiovascular disease (CVD), Fecal biomarkers, like fecal calprotectin (FC), often have difficulty coping and living with dif- may serve as a non-invasive, microscopic alterferent symptoms and treatments on a daily ba- native. sis. With multiple comorbidities, patients have Methods: Three patients with Crohnâ&#x20AC;&#x2122;s disease difficulty with normal daily activities, since provided fecal samples over a 66 week period. they are burdened by several symptoms from Fecal calprotectin scores were generating using the diseases. The goal of this study was to dean ELISA, and compared with SIBDQ scores, scribe self-care behaviors of current patients the Harvey Bradshaw Index, and Mayo 9 point with cancer, T2D, and CVD, and to identify scores for each patient. factors that impede self-care. Eight patients an- Results: FC levels appeared to follow the trend swered self-administered survey questions of the quality of life scores. At the pre-op about exercise habits, drinking habits, physical benchmark, Patient 1 had a HBI score of 10 and activity routines, healthy diet plans, medication a calprotectin level of 556 ug/g, meaning active usage, and rated their quality of life. Research- inflammation. At the 48 weeks HBI was 9 and ers also used semi-guided questions in conduct- calprotectin level was 850 ug/g. Patient 2 caling individual interviews that were digitally rec- protectin was its highest (16 weeks) at 78 ug/g, orded and transcribed. In general, patients who and had a correlated HBI score of 5. do more frequent physical activity tend to have

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Conclusion: Fecal calprotectin can be used to monitor patient response to treatment postoperation. FC followed expected inflammation trends after surgery and reflected patient response to treatment.

and cortical thickness, and biochemical markers. Detected calcifications were 3.2 mgHA higher in stage 4-5 and hemodialysis patients than the other groups. Significant correlations were found with calcium, PTH, BSAP, osteocalcin, P1NP, Trap 5B, and sclerostin levels and LLACs. Inverse relationships were found Anjali Gehani between bone measurements and calcifications, Assessment of the Bone Parameters and Vas- having more statistical significance after stage 4 -5. These findings implicate that biochemical cular Calcification Severity through HighResolution Peripheral Quantitative Comput- and bone parameters are interrelated in calcification formation and HR-pQCT is a reliable ed Tomography technique for future studies.

Chronic kidney disease (CKD) is associated with the progression of vascular calcifications and changes in bone structure parameters. Highresolution peripheral quantitative computed tomography (HR-pQCT) is a novel imaging technique used to provide images of bone microarchitecture and quantify arterial calcifications.

This study used HR-pQCT to quantify bone parameters and lower leg calcification severity (LLACs) of varying CKD patient groups to determine associations and the effectiveness of HR-pQCT. CKD groups stage 1-2, 2-3, 4-5, hemodialysis, and non-CKD patients were enrolled and compared for biochemical and bone microarchitecture data and calcifications. HRpQCT scans were obtained from the radius and tibia and calcifications were quantified using image processing, including a gauss-filter and dual-threshold seed-point segmentation technique. Univariate and multivariate statistical analyses, ANOVA, and Wilcoxon tests were performed on quartiled data adjusted for sclerostin to determine the correlation coefficients between LLACs and risk factors for severity, including volumetric bone density, trabecular

Megi Gjini Assessing the Role of Cytokines in the Immune Response in Acne Patients vs. Healthy Donors The onset of acne has been attributed to four key causes: abnormal follicular differentiation and increased cornification; abnormal activity of the sebaceous gland; Propionibacterium acnes; and inflammation and immunologic reaction. Over the years, there has been a growing interest in the role of the immune system in the disease and studies have identified the presence of cytokines IL-1B, IL-8, IL-10, IL-12, and TNFÎą, immune cell-signaling proteins, in both the early and late stages of acne. However, the role of the immune system in acne pathology is poorly understood. To better understand the role of systemic immune activation on acne, we have determined cytokines and chemokine expression signature in blood plasma of acne patients and healthy control subjects using the multiplex assay system. The level of proinflam-

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matory cytokines such as IL-3 (t-test, p≤0.06), IL-4 (t-test, p≤0.06), IL-6 (t-test, p≤0.06), IL-9 (t-test, p≤0.06), TNFα (t-test, p≤0.41), and TNFβ (t-test, p≤0.41) increased in the acne patients compared to the healthy subjects although statistically not significant. Hierarchical cluster analysis of cytokine and chemokine panel shows the clustering the proinflammatory cytokines in acne patients with 4 distinctive subgroups and 3 groups in the cytokines. As expected, subject clustering is not completely acne versus healthy subjects since measured analytes are indication of immune activation. The higher expression level of cytokines critical for the T cell activation in acne patients suggest an underlying immune activation in the acne patients despite the limited size of study cohorts.

Maya Goodwin Guenon Premolar Enamel Thickness The investigations of the factors that influence enamel thickness in primates provide us insight regarding how natural selection may shape enamel thickness. This study tested whether enamel thickness increases from anterior to posterior teeth, and whether diet or the maximum latitude of species distribution range closely relates to enamel thickness in the guenons (tribe Cercopithecini, family Cercopithecidae). Because guenons are a species-rich tribe, they can be studied as a model of enamel thickness evolution that controls deep phylogenetic divergence. Using ImageJ on Cintiq 13HD tablet, various measurements were taken from 3D μCT -scanned images of virtually-sectioned 30 guenon teeth. Then Absolute Enamel Thickness

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(AET) and Relative Enamel Thickness (RET) were computed. This study found that differences between sexes, upper/lower jaws, left / right sides of jaws were not significantly significant. However,enamel thickness in PM4 was significantly thicker than that of PM3. Thus, the hypothesis that enamel thickness increases from anterior to posterior teeth was supported. Furthermore this study found significant species differences in AET and RET. The general linear models (GLM) revealed that AET-maximum latitude is expressed as y= 0.013x+0.27 and the GLM of the RET maximum latitude of the species range fit was y=0.42x +11. These results support my hypothesis. Contrary to my hypothesis, no close relationship between diet and enamel thickness was found. ANOVA on RET show that tooth Position (PM3 or PM4) has the greatest predictable power followed by Species and Maximum Latitude, but the residual of 43.17 indicates that some unknown factor(s) also appear to influence enamel thickness.

Clyde Huibregtse Formulating a Novel Examination for Mold cognitive Impairment as a Prerequisite for Alzheimer's Disease Mild Cognitive Impairment (MCI), manifesting near the latter end of the 55-75 years of age spectrum, is a mental prerequisite for Alzheimer’s Disease (AD). Early diagnosis of AD, however, has been elusive because it requires a physical cross sectional analysis of the brain (performed postmortem), or an invasive, expensive and time-consuming protein detection examination. Currently, an examination known as

the Mini Mental State Examination (MMSE) is used to identify the likelihood of dementia. The MMSE, however, does not evaluate properly certain aspects of the cognitive function of individuals with MCI, as it tends to group patients with control subjects, while ignoring the separation that occurs in most other forms of logical memory or visual reproductions. Hence, a novel examination was created to address these deficiencies and enable a more accurate identification of those with MCI. A novel test incorporating MATLAB operations was developed. The test involved viewing images of faces, memorizing those images, and recalling and identifying familiar faces. Across control patients, there appeared no statistically significant correlation between MMSE score and novel examination score. However, these data do create a baseline for future comparison to demented or MCI patients. Scores lower than this standard of normalcy could lead to earlier classification as at risk for dementia.

Nathaniel Iskhakov The Stability of OVA257-264 and LCMV GP33-41 epitopes on MHC-1 affect IL-2 Dependency during Primary and Secondary Infection T cells proliferate if they recognize an antigen on the surface of phagocyte. The recognition of the peptide can be significantly reduced if the stability of the antigen is lessened. The discovery of a mutation in a strain of mice can be used as a tool to determine the immunological effects of the stability of a peptide. The stability of two peptides, OVA257-264 and LCMV GP33-41,

were reversed and were introduced into mice along with Listeria. Originally wild-type mice infected with Listeria with wild-type OVA257264 required interleukin-2 for T cell proliferation in the primary infection, but not recall infection. The reverse was found in mice infected with the GP33-41 peptide. When the stability of OVA257-264 was decreased, the role of IL-2 in T cell proliferation was only vital during recall infection, not primary infection meaning that the stability of OVA257-264 epitope affects IL2 dependency during primary and secondary infections. Because of this we would need to bear in mind the antigens we use and whether they will induce T cells that require IL-2.

Anisha Jain Sensitivity and Specificity of an Eye Movement Tracking Based Biomarker for Concussion The purpose of this study was to determine the sensitivity and specificity of an eye tracking method as a classifier for identifying concussion. Both brain injured and control subjects were tracked using Eyelink 1000 eye tracker and administered the SCAT 3. The results of eye tracking method based classifier models were validated against a dataset of individuals not used to build the models. The area under the curve (AUC) of receiver operating characteristics (ROC) was examined. An optimal classifier based on best subset had an AUC of 0.878, and a cross-validated AUC of 0.852 in CT subjects and an AUC of 0.831 in a validation dataset.

The misclassification rate in the external dataset was 13%. If one defines concussion as (1) trau-

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matic injury resulting in ED evaluation (2) sufficient indication for a CT scan of the brain (3) SCAT3 SSS of >40 and (4) SCAT3 SAC score of <24, then it is possible to generate an eye tracking based biomarker that enables detection of concussion with reasonably high sensitivity and specificity.

Alekya Kaveti CD4+ Treg Cells with Antigen Specificity for tau pathology of Alzheimer's Disease in Mouse Models Immunotherapy has been a promising field of investigation for Alzheimer's disease (AD). The root causes of AD are neurofibrillary tangles and tau plaques. Tau protein, due to mutations in gene 17, causes tau protein to abnormally form. Even though the original form of tau protein is to form microtubules, tau sheets aggregate and instead form plaques. These plaques accumulate and the immune system reacts by releasing microglias and astrocytes. The reason for the abnormality or aggregation has not been well understood. Thus, one field of research if focusing on diminishing the tau related pathology. Passive immunization, or injections of antibodies for tau related pathology has been done, and seems to be the most effective. In a similar way, genetically engineered t-lymphocytes have been used, which have receptors that target tau pathology. It would be observed that CD4+ T cells can be used to decrease the amount of tau pathology observed. This is a promising notion as adoptive therapy, originally used on cancer research, can be used for treating neurodegenerative conditions.

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Lakshay Khosla Mathematical derivation and analysis of the lowest energy states in a 2-particle system Magnetic disks with nanoparticles were used to create quantum computers for use in the future.

These disks behave differently from regular disks due to the presence of the nanoparticles.

Particles generally differ from each other in behavior, and their magnetic properties depend strongly on the direction of the magnetic field, a property known as anisotropy. Single particle systems have been analyzed, but analyzing multiple particles in a system has been elusive. In this study, the lowest energy states of a twoparticle system, as it relates to the magnetization field angles of each particle, were examined. The computer program, Wolfram Mathematica and calculus were employed to determine this relationship. After a graphical analysis of a derived equation, Energy[θH1, θH2, θ1, θ2, H, d]= -H*Cos(θ1) – d*Cos^2(θH1- θ1) H*Cos(θ2) – d*Cos^2(θH2- θ2), it was noted that the smaller magnetization field angles had the lowest energy states. This result will lead to further development of multiple particle models, which will one day help make up the magnetic disks of quantum computers.

Nanami Kubota Global drivers of beta diversity in birds Understanding how biological diversity is spatially organized on Earth is one of the central

questions in biological sciences. This knowledge will help us understand how current global change will impact biodiversity at a global scale in the future. Many previous studies have addressed the main drivers of species diversity at a local scale (i.e. alpha diversity).

However, not much is known about how the factors that drive the observed differences in species composition among locations (i.e. beta diversity). In the present work, we studied the factors that control beta diversity at a global scale, using as a case study all bird species of the world (n = 10,419 species). Specifically, three main drivers hypothesized to control beta diversity were tested: 1) energy and water availability, 2) climatic stability and 3) environmental heterogeneity. These three hypotheses were tested for total beta biodiversity (βsor) and its two intrinsic components: turnover (βsim) and nestedness (βnes). To do so, the landmasses of Earth were divided into 51,120 1° by 1° (latitude by longitude) cells and the three beta diversity indexes (βsor, βsim, βnes) calculated for all bird species of the world. The climatic and environmental factors used to test the three hypotheses were present temperature, present precipitation, the ranges of the previously mentioned two variables along with altitudinal range, temperature during the Last Glacial Maximum (LGM, i.e. 20,000 years ago), LGM precipitation, difference in present and LGM temperatures, and difference in present and LGM precipitation (a total of nine variables). The results showed that environmental heterogeneity was the most supported hypothesis for the total and turnover component of beta diversity, as assessed from the values of explained variance (r2) from linear regression (βsor = 17.22%, βsim

= 22.51% for altitudinal range). However, the nestedness component of beta diversity was better explained by water availability in both current times (r2 = 12.51%) and LGM (r2 = 13.00%). Surprisingly, the climatic stability hypothesis was only weakly supported in these analyses. Overall, the results constitute one of the first tests of the drivers of beta-diversity of birds at a global scale and is an important step towards to our understanding of the spatial organization of biological diversity in our planet.

Nora Kuka The role of beta amyloid plaques and nuerofibrillary tangles in Alzheimer’s disease

Alzheimer’s disease (AD) is the most common form of dementia. It is a very widespread problem and the number of people affected by AD is only expected to increase. Several genes may be involved in the development of AD, including APOE, APP, PSEN1 and PSEN2. These genes can be responsible for early onset AD. Some neuropathological hallmarks of AD include beta -amyloid plaques and neurofibrillary tangles.

Currently, there are treatment options available but there is still no cure.

Ben Lipkin New compounds exhibit structural interaction with prion-related-protein TIA-1 While most often associated with neurodegener-

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ative disorders, non-pathogenic prion-like proteins function naturally within the body. An example of such a protein is t-cell-restricted intracellular antigen 1 (TIA-1), which plays a role in the cellular stress response. To further examine the role of this protein, we decided to first find a way to manipulate this proteinâ&#x20AC;&#x2122;s ability to change conformation and form aggregates.

Since antioxidants have been implicated as antiprion compounds, we examined the effects of 84 antioxidant compounds on TIA-1 oligomerization using an in vitro FRET assay. The top drug decreasing FRET (Compound A) and the top drug increasing FRET (Compound B) were used for further experimentation. A ThT assay was used to determine how these drugs affected TIA-1 conformational state, and SDS-PAGE and Western Blot were used to determine if these compounds resulted in any TIA-1 complexes. We found that Compound A decreased the quantity of TIA-1 in the aggregation prone state, while Compound B increased it. Compound B also resulted in a heavier weight TIA-1 aggregate on Western Blot. These results will allow further study into TIA-1 as well as other prion-related-proteins. The structural interactions between these compounds and prions may ultimately reveal a window into prion structure.

Abdallah Mohamed Antagonistic roles of EED and histone H3K36me2 in the propagation of histone H3K27me3 Chromatin remodeling can lead to repressed or activated chromatin states, and these changes

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can be epigenetic, preserved over multiple generations. Repressed chromatin is inaccessible to transcription factors, resulting in gene silencing.

In contrast, activated chromatin is associated with activation of gene expression. Changes in chromatin state have been linked to developmental defects and diseases such as cancer.

Thus it is important to understand how chromatin states are established and maintained. Modification of histone proteins that comprise the nucleosome plays a major role in regulating chromatin structure. Histone H3 protein modifications have been associated with both repressed and activated chromatin states. Polycomb repressive complex 2 (PRC2) is a protein complex that trimethylates lysine 27 on histone H3 (H3K27me3), a modification correlated with repressed chromatin. The MMSET/NSD2 protein dimethylates lysine 36 on histone H3 (H3K36me2), a modification correlated with activated chromatin. How these histone H3 modifications are regulated and propagated to either maintain or cause changes in chromatin structure is not well understood. This study provides in vitro evidence that H3K27me3binding activity of the EED protein, a component of PRC2, is required for propagation of H3K27me3 at nearby chromatin sites. This study also provides in vitro evidence that presence of H3K36me2 leads to reduced propagation of H3K27me3, suggesting that the role of H3K36me2 in activating chromatin involves modulation of H3K27me3. Furthermore, creation of a novel cell line that will allow in vivo studies of the role of PRC2 in propagation and maintenance of repressed chromatin is described, enabling a new scope of research on PRC2 that was previously inaccessible. This

work adds to our knowledge of how epigenetic marks like H3K27me3 are established and maintained and has important implications for understanding the role of chromatin structure in development and disease.

es. A systematic review was conducted by searching electronic databases (PubMed and EMBASE), including literature on disasters, mental health, and blood pressure. Studies addressing natural disasters and their effects on mental health, stress, and blood pressure were identified. Natural disasters potentially influence Ethan Mui higher blood pressure in people including pregEfficiency of GPU based Computing Clusters nant women. Severity of exposure is the major predictor of mental health and blood pressure. versus CPU based Computing Clusters Pregnant women may be especially vulnerable Parallel processing is commonly used for large to increased blood pressure caused by the disasscale data calculations and simulations. It is de- ter. These results suggests the need for preventafined as the separation of a main processing task tive measures to reduce long-term effects of the disaster. into multiple smaller tasks, each of which is then sent to itâ&#x20AC;&#x2122;s own computing core. It has been a common point of debate over the recent years Santiago Munoz whether a GPU or CPU based computing cluster Neuroglobin in the Pons of Healthy and Auswould be more efficient in carrying out protistic Individuals cessing operations. A possible experiment which could be carried out to determine speed, efficiency, and accuracy of each processor type is a protein analysis comparison. Results favorable and unfavorable to the hypothesis could be predicted, showing the CPU cluster or the GPU cluster as the primary contender for optimal processing times while maintaining accuracy.

Neuroglobin (Ngb) is a protein that was recently discovered in 2000. When cells overexpressed Ngb hypoxia induced cell death failed to occur, in autism angiogenesis points to hypoxia. The point of this experiment is to determine whether there is any difference in the amount of Ngb activity occurs in the pons of autism and control subjects. By staining for the Ngb protein, we Nicholas Mui will be able to determine which parts of the The Effect of Disaster on Blood Pressure: A ponsâ&#x20AC;&#x2122;s express Ngb. If a difference between autism and control is shown it could point to difSystematic Review ferences in the way the oxygen system is reguDisaster increases community psychopathology, lated or behaves in the pons. In control samples the stained cells were cluttered together and they with depression and PTSD being especially spread horizontally across the tissue. However common. This may lead to higher blood pressure and increased risk of cardiovascular diseas- in autism the stained cells were scattered and

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specific relationship that occurs between Ngb and autism, the results of this experiment definitely points in the direction that Ngb expression in the pons in control and autism subjects show distinct differences.

in most mature piRNA levels, but further optimization is necessary for both the IP/Western and the qPCR to make full conclusions.

Nicholas Persaud Hobart Pao The role of the RNA exosome in DNA methylation via the piRNA pathway

The Effect of Phase of Drug Use on Levels of the Serotonin 1b Receptor

Drug abuse is a major problem worldwide and it affects people of all ages. Many people develNoncoding RNAs (ncRNAs) are RNAs that op disorders and other diseases as a result. may potentially control transcription and trans- Many lives are being lost as well as a result of lation. One such ncRNA is piRNA, which tar- overdose. Researchers have conducted experigets histone methylation to specific sequences ments in order to combat the issues of addiction and ends in transcriptional repression. ncRNAs, and abuse. Dr. Alexander Neumeister conductif unregulated, can cause serious problems, and ed an experiment on alcohol addicted patients they do; piRNAs and piRNA pathway genes (Neumeister, 2010) and then another experihave been found to be upregulated in various ment on cocaine addicted patients (Neumeister, cancers, and in the same cancers, aberrant his- 2012) . Neumeister focused on the levels of sertone methylation patterns were also observed. otonin in the patients and found that there were But piRNAs, especially their biogenesis, are different trends in both experiments. Using this poorly understood. There is an unknown exonu- information it was hypothesized that the phase clease that trims the 3’ ends of piRNAs, and of drug use affects the levels of serotonin in the thus enables them to bind and target specific patients. sequences properly. The RNA exosome is a good candidate for the 3’ end trimmer because Sanjida Rahman it contains 3’-5’ exonucleases, and it has also Depletion of the epigenetic regulator PHF14 been found to be upregulated in the same cansensitizes HeLa cells to the anti-cancer drug cers where piRNAs and piRNA pathway genes olaparib have been upregulated. A direct connection between the RNA exosome and the piRNA path- Our cellular genomes are continuously being challenged by the many DNA damage inducing way would be of use to the generation of new agents which may result in genomic aberrations cancer treatments, because such a connection would implicate the RNA exosome in the regu- and lead to unwanted cellular events such as lation of histone methylation. Using the BmN4 senescence, apoptosis or uncontrolled growth, cell line, IP and Western blotting has not been and diseases such as carcinogenesis. To counable to confirm that the RNA exosome interacts teract DNA damage, eukaryotic cells have with piRNA-associated proteins, but according evolved the DNA damage response (DDR) to to qPCR and specific optimizations, knockdown respond to the presence of DNA damage and of the RNA exosome usually causes a decrease ensure appropriate cell function following damage repair. The DDR is subject to epigenetic

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regulation through changes in chromatin structure. PHF14 is a plant homeodomain finger (PHD) containing protein that is highly conserved in eukaryotic cells from yeast to humans.

Recent studies have shown that the PHF14 protein participates in DDR. It has been proposed that PHF14 regulates transcription via binding to epigenetic marks on histones in chromatin.

However, very little is known about the precise role of PHF14 in DDR. In this study, it is demonstrated that PHF14-depleted HeLa cells exhibit sensitivity to the DNA damaging agent olaparib, but not to camptothecin or hydroxyurea. These observations suggest that PHF14 plays a role in protecting HeLa cells from certain types of DNA damage.

Shanjida Salam Assessment of urban tree health in the Bronx and Queens for trees sampled in 2014 and 2015 Green infrastructure (GI) in cities provides major benefits to urban environments, especially in terms of helping manage stormwater runoff and improving water and air quality. However, managing and maintaining trees and GI installations is extremely crucial in making sure that those benefits are provided. This study is a continuation and expansion of the Green Infrastructure Plant and Soil study begun in 2014 dedicated to assessing the health of trees in urban areas of the Bronx and Queens using sampling methods created by the USDA Forest Service. Results from 2015 show that tree health varied across borough and land use, with trees in the Bronx exhibiting more signs of stress than those in Queens, and trees in residential areas showing less signs of stress than in commercial and

industrial areas. The year the tree was sampled in also provided insight into the health of the tree. Our results showed significant improvements in health in 2015, two years after they were planted, as compared to in 2014 when they were first sampled. This study helps to further enhance our understanding of what variables to consider when managing green infrastructure in urban areas to help maximize the benefits.

Rui Si Bafetinib Shows Potential as an Inhibitor for Chemotherapeutic Multidrug Resistance Mediated by BCRP/ABCG2 Transporter Multidrug resistance in chemotherapy is a big obstacle to overcome for effective treatments in cancer. In this study, a BCRP-mediated resistance model was created and validated, and applied this model to screen out novel potential BCRP inhibitor to overcome resistance by inhibiting BCRP. BCRP was successfully transfected into HEK293 cells. The western blot test and immunofluorescence test were able to show that the BCRP was successfully expressed and located in cell surface. MTT assays of chemotherapeutic drugs and inhibitors proved the function of transfected BCRP, and we were also able to show that the resistance was directly related to BCRP introduced by transfection.

Bafetinib was screened out as a novel potential BCRP inhibitor through our system.

Kevin Turaczy The Effects of the Restoration of an Oak Forest Ecosystem on its Energy Budget When an ecosystem is disturbed, its equilibrium is disrupted and the surviving organisms must work towards restoring the energy flow equilibrium. One particular organism that contributes

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towards this restoration is Aranea. Exactly how much energy the spider contributes seasonally is unknown. Three-hundred square meters of deciduous forest land was cut in Cornwall, New York to replicate a disturbance. Spider collection began the following year in the summer of 2009 until 2012. Collection of other invertebrates in the forest began in 2009 until 2012.

Pitfall trapping was used to capture the organisms. For spider biomass, the largest percent increase was exhibited in the collection period May 21-31 to June 1-9 with a percent change increase of 1338.1%. The largest percent change decrease for spider biomass was exhibited in the collection period July 1-9 to July 1019 with a percent change decrease of -71.2%.

There were constant shifts between peaks and dips of positive and negative seasonal changes in energy. The large percent increase within the first week of June shows that spiders may contribute the most in this week and that they are essential to forest restoration within this time period. This study suggests that spiders occupy this specific niche and other invertebrates may also have specific time periods in which they essential towards the restoration of the ecosystem.

Jack Wang Modelling Homoserine Lactone Transfer via a Visual Modular Biosensor In our research, we constructed a biosensing system that can detect the presence of homoserine lactone, a signaling molecule that bacteria use to control population density and collective behavior. This behavior is called quorum sensing, and is used universally in the natural world.

Not only is this behavior ubiquitous in prokaryotes, but also in larger group-associated organ-

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isms such as insects, which use quorum sensing to communicate as a centralized system. Our system explores this phenomenon through single celled organisms, E. coli, in hopes of being able to limit or even control how much group oriented organisms can communicate. The plan was as follows: If homoserine lactone was detected by the biosensor, then the biosensor would produce blue chromoprotein, which would provide a visual indication that the bacteria were preparing to grow or adapt to a new environment. Because the biosensor was unable to detect the homoserine lactone, we used ultraviolet (UV) light as a stimulus to be detected instead. Insights into signaling molecules like homoserine lactone can reveal more information about quorum sensing, or how bacteria communicate. Such discoveries can be useful to microbiologists, hospitals, the military, and the average consumer.

Siyu Wu Lysine Acetylase GCN5B mediates the GCN5B interaction complex through Lysine K857 and K941 Post translational modifications, and in particular, histone acetylation, has always played a major role in gene expression of eukaryotes. However, the method in which histone modifying enzymes interact with other factors to facilitate gene regulation is scarcely known. Toxoplasma gondii is known for having two unique GCN5 histone acetyltransferase homologues, GCN5A of which is responsible for the alkaline stress response of toxoplasma tachyzoites. GCN5B was unable to be knocked out, suggesting of its critical importance to T. gondii tachyzoites, until a nullified mutant GCN5B line was intro-

duced which displayed an abnormally slow proliferation rate and potential. The GCN5B complex also is missing any conventional DNAbinding domains such as GCN4 and ATF4, instead having two plant-like AP2 transcription factors as substitute. Though AP2 is a part of the GCN5B complex and may act as a substitute DNA-binding domain, the identity of the acetyl group transferring domain in GCN5B is yet to be discovered. Through purifying the complexes of different variations of GCN5B, each variation lacking a specific acetyl group transferring domain, the two acetyl transfer domains: K857 and K941, though containing significant correlation to a large portion of the confirmed GCN5B complex, do not correlate with the interaction between GCN5B and any AP2.

The two acetyl transfer domains: K857 and K941, play a significant, but not critical role in the interactions between GCN5B and its interaction complex.

Yan Zhang The Effect of Wind Speed on Thermal Imagery Data Combined sewer overflow is a huge problem being investigated within urban cities. The main cause of combined sewer overflow is water runoff, which overflows a combined pipe system.

This causes a huge disruption in urban ecosystems by exposing many marine ecosystems to chemicals. It is shown that chemicals found in combined sewer overflow causes a variety of problems to humans as well. However, today, some people propose a possible solution of using green infrastructure to counteract the growing combined sewer overflow problem. Because of how surrounding temperature correlates with a plantâ&#x20AC;&#x2122;s water usage, thermal imagery can be a quick alternative way to measure how much

water a certain green infrastructure may be using. The results show how unsuitable thermal imaging can be applied to different green infrastructure as green infrastructure have various environmental factors unlike greenhouses; they may be the best place where thermal imaging may work the best where favorable conditions can be kept constant.

Jeffrey Zhang-Sun Speciation and biogeography of the Trumpet Manucode species-complex (Paradisaeidae: Phonygammus) The Trumpet Manucode (Phonygammus keraudrenii) is a species belonging to the family Paradisaeidae, the Birds-of-Paradise. Found on New Guinea and North Queensland, Australia, these birds are characterized by their perplexing distribution patterns. It is accepted that there are nine different subspecies of P. keraudrenii, but most of them are not clearly defined. Preserved study skin specimens of the birds were collected and assigned a paratype name 65-120 years ago based on morphology. Unfortunately most of the specimens are incorrectly classified due to their iridescent feather coloration. Trumpet Manucode subspecies are found in their own areas of endemism but distributions often overlap across their large ranges. In order to resolve the evolutionary history of this species-complex, toe-pad samples collected from archived studyskins of all subspecies, covering as much of their distributions as possible, were subjected to polymerase chain reaction amplification and sequencing of the mitochondrial ND2 gene. Sequence data were used to construct phylogenetic trees based on molecular homologies, using maximum parsimony and maximum likelihood analyses. These

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phylogenetic results were compared to the morphological and geographic variation between the preserved samples to further evaluate and clarify the taxonomic status of each proposed subspecies. This study resolves the taxonomic status of the entire species and provides the first phylogenetic hypothesis for the Trumpet Manucode, also providing interpretations of possible influences on the joint history of the Trumpet Manucode. It was found that the subspecies P. k. hunsteini, is sister to the rest of the species. P. k. diamondi and P. k. purpureoviolaceus do not differ enough to be considered different taxa. Specimens from the western half of New Guinea were not well distinguished on the evolutionary tree resulting in three former subspecies being regrouped as one, P. k. keraudrenii.

The phylogenetic data were also used to estimate the timetree of Trumpet Manucode species diversification and to reconstruct the history of speciation across New Guinea in correlation with major geologic events. It was estimated that P. k. hunsteini split from other subspecies 2.4-2.1 mya, implying that the islands they are located on experienced continental drift around that time. P. k. neumanni and P. k. adelberti, are estimated to have split off 1.2-0.9 mya, suggesting that the mountain ranges they are found on were separated from the rest of New Guinea around that time, most likely due to formations of valleys or lowlands.

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Award Winners in Biology 2016 Intel STS 2016 Semifinalists Award Madeline Leah Abrahams, Anusha Bishop, Arun Bishop, Therese Chan, Ariana Mastrogiannis, Aliyah Shian Taylor, and Jing Xu. ISEF Finalists Anusha Bishop- Animal Sciences Yi Chen- Cellular & Molecular Biology Abdallah Mohamed- Cellular & Molecular Biology

New York City Science and Engineering Fair Finalists NYCSEF First Award Anusha Bishop - Animal Sciences Yi Chen- Cellular & Molecular Biology Abdallah Mohamed- Cellular & Molecular Biology Kalyani Gopalkrishna- Earth & Environmental Sciences Neeraj Sakhrani- Earth & Environmental Sciences NYCSEF Second Award Sarah Fineman- Behavioral & Social Sciences Tehani Gunaratna- Behavioral & Social Sciences Ben Lipkin- Biochemistry Hobart Pao- Cellular & Molecular Biology Lucy Lee- Chemistry Jessica Li- Computer Science Therese Chan- Engineering Arsalaan Ansari- Medicine & Health Sciences Jing Xu- Medicine & Health Sciences NYCSEF Third Award Ben Davar- Animal Sciences Soulet Ali- Behavioral & Social Sciences Jacob Levitt- Behavioral & Social Sciences Nell McKenna- Behavioral & Social Sciences Junior Science and Humanities Symposium Quymbee Chen – 1 place Mathematics and Computer Science; Karina Kalpaxis – 1st place Behavioral and Social Sciences; Joshua Zakharov – 1st place Physicis; Therese Chan- 2nd place Engineering; Lucy Lee--2nd place Chemistry; Abdallah Mohamed- 2nd place Biology; Isabel Billenge- 3rd place Chemistry. st

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Photo Credit: Maya Goodwin â&#x20AC;&#x2DC;16 The Journal of Biology is published annually by the Students of the Bronx High School of Science.

The Bronx High School of Science The Journal of Biology, Rm 223 75 West 205th Street Bronx, NY, 10468

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