The greatest journey ever undertaken left behind a trail of unanswered questions: How did our species arise and spread around the globe to become the most dominant creature on the planet? Part of the answer came two decades ago, when scientists stunned the world with the finding, based on genetic research, that all humans alive today can claim as a common ancestor a woman who lived in Africa some 150,000 years ago — dubbed, inevitably, “Eve.” But while the notion of an African origin of the human family has grown to be accepted by most scientists, the details of how Eve’s ancestors swept out of Africa to populate the rest of the world have remained unclear.
the earliest member of the human species appeared about two million years ago in the Great Lakes region of Central Africa.
Dr. Albert Chuchward, distinguished scholar, anthropologist, and archeologist theorizes that the earliest member of the human species appeared about two million years ago in the Great Lakes region of Central Africa. This early human species eventually spread over the entire continent. Many individuals in Dr. Churchward’s field generally agree with his theory, including Dr. L.S.B. Leakey. In 1963, Leakey found primitive human fossils, 1.2 million years old in East Africa. Further discussion on this theory was published in Newsweek Magazine, January 11, 1988, in an article called “The Search for Adam & Eve.” The subject was about the collection and testing of a global assortment of genes.
to colonize the rest of the world.
A trail of DNA was found that led them to a single woman from whom we all descended. The evidence indicates that Eve lived in Sub-Saharan Africa, between 80,000 and 200,000 years ago. These descendants began migrating from their original homeland, inhabiting the whole world.
The African ancestry of human is now generally accepted as a fact. Dr. Eric Higgs, of Cambridge University has made a study of the migration of ancient men, and claims that the first man of Europe came to the continent from central and east Africa about 200,000 years ago. Professor Chester Chard, of the University of Wisconsin, has studied the routes of early men who left Africa to colonize the rest of the world, and he has concluded that there were four prehistoric migration routesfrom Africa to Europe.
The route of migration out of Africa was into the Middle East and then to the rest of Eurasia, the Americas, and Oceania.
Professor Leakey was asked if any of these early Africans reached the New World, and he answered: “It is inconceivable that man, the most curious and mobile of all animals, would not have come to America when the elephants, the tapirs and the deer came from Asia. ... Man spread out from Africa to Asia to Europe. It is inconceivable that he would stay out of America.”
It is inconceivable that man, the most curious and mobile of all animals, would not have come to America when the elephants, the tapirs and the deer came from Asia...
In 1988, Christopher B. Stringer and Peter Andrews, of the British Museum of Natural History confirmed the single-origin theory, that Homo Sapiens had evolved from an African Homo Erectus group, 200,000 years ago who had later migrated to Asia and Europe about 100,000 later. Both scientists contend that fossil evidence supports their single-origin theory. They also note that the oldest modern looking human fossils are only 35,000 years old.
In 1965, the 2.4 million years old human skull remains were found in Kenya. This new date places the origin of human beings within the period of major climate change, a global cooling, which is already believed to have caused other mammals to undergo evolutionary change. Geologist, John Martyn discovered the fossils while working in the Chemeron Beds in Kenya’s Great Rift Valley. The date of the skulls was determined using a new scientific method called, Agron. These discoveries help to validate the fact that mankind originated in Africa. Humans born around the Great Lakes region, so very close to the equator, would have been very heavily pigmented. Gloger’s Law states that warmblooded animals born in such an equatorial region as the Great Lakes and Kenya will secrete a dark pigment called eumelanin
Scientists are calling her Eve. But her name evokes too many wrong images - the weak-willed figure in Genesis, the milk-skinned beauty in Renaissance art, the voluptuary gardener in “Paradise Lost” who was all “softness” and “meek surrender” and waist-length “gold tresses.” ” The scientists’ Eve - one of the most provocative anthropological theories in a decade - was more likely a darkhaired, black-skinned woman, roaming a hot savanna in search of food. She was muscular and strong; she might have torn animals apart with her hands, although she probably preferred to use stone tools. She was not the only woman on earth, nor necessarily the most attractive or maternal woman. She was simply the most fruitful, if that is measured by success in propagating a certain set of genes. Hers seem to be in all humans living today: 5 billion blood relatives. She was, by one rough estimate, your 10,000th-great-grandmother. The “discovery” of Eve rekindled scientists perhaps the oldest human debate: where did we come from? They also confirmed a belief that existed long before the Bible. Versions of the Adam-andEve story date back at least 5,000 years and have been told in cultures from the Mediterranean to the South Pacific to the Americas. The mythmakers spun their tales on the same basic assumption as the scientists: that at some point we all share an ancestor.
the Bible’s Eve was calculated to have lived 5,992 years ago.
Eve has provoked a scientific controversy bitter even by the standards of anthropologists, who have few rivals at scholarly sniping. Their feuds normally begin when someone’s grand theory of our lineage is contradicted by the unearthing of a few stones or bones. This time, however, the argument involves a new breed of anthropologists who work in air-conditioned American laboratories instead of dessicated African rift valleys. The scientists don’t claim to have found the first woman, merely a common ancestor - possibly one from the time when modern humans arose. What’s startling about this Eve is that she lived 200,000 years ago. This date not only upsets fundamentalists, but also challenges many evolutionists’ conviction that the human family tree began much earlier. Trained in molecular biology, they looked at an international assortment of genes and picked up a trail of DNA that led them to a single woman from whom we are all descended. Most evidence so far indicates that Eve lived in sub-Saharan Africa,though a few researchers think her home might have been southern China. Meanwhile, geneticists are trying to trace our genes back to a scientifically derived Adam, a putative “great father” of us all. As is often the case, paternity is proving harder to establish: the molecular trail to Adam involves a different, more elusive sort of DNA.
The evolution from archaic to modern Homo sapiens seems to have occurred in only one place, Eve’s family. The most controversial implication is that modern humans didn’t slowly and inexorably evolve in different parts of the world, as many anthropologists believed. The evolution from archaic to modern Homo sapiens seems to have occurred in only one place, Eve’s family. Then, sometime between 90,000 and 180,000 years ago, a group of her progeny left their homeland endowed apparently with some special advantage over every tribe of early humans they encountered. As they fanned out, Eve’s descendants replaced the locals, eventually settling the entire world.
Some “stones-and-bones” anthropologists accept this view of evolution, but others refuse to accept this genetic evidence. They think our common ancestor lived much farther in the past, at least a million years ago, because that was when humans first left Africa and began spreading out over the world, presumably evolving separately into the modern races. As the veteran excavator Richard Leakey declared in 1977: “There is no single center where modern man was born.” But now geneticists are inclined to believe otherwise, even if they can’t agree where the center was. “If it’s correct, and I’d put money on it, this idea is tremendously important,” says Stephen Jay Gould, the Harvard paleontologist and essayist. “It makes us realize that all human beings, despite differences in external appearance, are really members of a single entity that’s had a very recent origin in one place. There is a kind of biological brotherhood that’s much more profound than we ever realized.” This brotherhood was not always obvious in Chicago two months ago, when the Eve hypothesis was debated by the American Anthropological Association. Geneticists flashed diagrams of DNA, paleoanthropologists showed slides of skulls and everyone argued with everyone else. “What bothers many of us paleontologists,” said Fred Smith of the University of Tennessee, “is the perception that this new data from DNA is so precise and scientific and that we paleontologists are just a bunch of bumbling old fools. But if you listen to the geneticists, you realize they’re as divided about their genetic data as we are about the bones. We’re not any more bumbling than they are.” Dispite of their disagreement, they left Chicago convinced they’re closer to establishing the origin of humanity. To make sense of their bumbling toward Eden, it is best to go
...all human beings, despite differences in external appearance, are really members of a single entity that’s had a very recent origin in one place.
back to one ancient relative accepted by all scientists. That would be the chimpanzee. But more skeletons kept turning up across Europe and Asia. Anthropologists realized that Neanderthal man was one of many brawny, beetle-browed humans who mysteriously disappeared approximately 34,000 years ago. These early Homo sapiens, incidentally, were not stooped. Nor did they fit the stereotype of the savage cave man. Their skulls were thicker than ours, however, their brains were as large. Their fossils show that they cared for the infirm elderly and buried the dead. It seemed they might be our ancestors after all.
Fossil hunters in Asia more than a half century ago found the still older bones of Java man and Peking man, who had smaller brains and even more muscular bodies. These skeletons dated back as far as 800,000 years. Perhaps they represented evolutionary dead ends. Or perhaps they, too, were human ancestors, with their descendants evolving into modern Asians while the Neanderthals were becoming modern Europeans - a process of racial differentiation that lasted a million years.
It appeared that ancient humans traced their lineage back to Africa; that was the only place with evidence of humans living more than a million years ago.
It appeared that ancient humans traced their lineage back to Africa; that was the only place with evidence of humans living more than a million years ago. Stone tools were invented there about 2 million years ago by an ancestor named Homo habilis .Before him was Lucy, whose 3 million-year-old skeleton was unearthed in the Ethiopian desert in 1974. Lucy was three and a half feet tall and walked erect - not ape, not quite human. At some point her hominid ancestors began evolving away from the forebears of our closest relative, the chimpanzee. But when? Most anthropologists thought it was at least 15 million years ago, because they had found bones from that era of an apelike creature who seemed to be ancestral to humans but not apes. Then, geneticists intruded with contradictory evidence, led in 1967 by Vincent Sarich and Allan Wilson of the University of California, Berkeley. They drew blood from baboons, chimps and humans, then looked at the molecular structure of a blood protein that was thought to change at a slow, steady rate as a species evolved. Until the molecular biologists were introduced, the role of the chimpanzee in evolution was dependended on the usual evidence: skeletons. Scientists have relied on bones ever since the 1850s, when Darwin published his theory of evolution and some quarriers unearthed a strange skeleton in Germany’s Neander Valley. Was the stooped apelike figure a remnant of an ancient race? Leading scientists thought not. One declared it a Mongolian soldier from the Napoleonic Wars. A prominent anatomist concluded it was a recent “pathological idiot.�
Homo habilis “Handy Man” Java man, Peking man-specimens of Homo erectus The discoverers of this skull celebrated by staying up all night drinking beer, and they named her after the Beatles’ song that kept blaring on the camp’s tape player, “Lucy in the Sky with Diamonds.”
There were major differences between the molecules of chimps and baboons, as expected, since the two species have been evolving separately for 30 million years. But the difference between humans and chimps was surprisingly small - so small, the geneticists concluded, that they must have parted company just 5 million years ago. Other geneticists used different techniques and came up with a figure of 7 million years. Traditional anthropologists did not appreciate being told their estimates were off by 8 million or 10 million years. The geneticists’ calculation was dismissed and ignored for more than a decade, much to Wilson’s displeasure. “He was called a lunatic for 10 years. He’s still sensitive,” recalls Rebecca Cann, a former colleague at Berkeley who is now at the University of Hawaii. But eventually the geneticists were vindicated by the bones themselves. As more fossils turned up, anthropologists realized that the 15 million-year-old bones didn’t belong to a human ancestor and that chimps and humans did indeed diverge much more recently. Wilson, who won a MacArthur “genius grant” in 1986, is once again trying to speed up evolution. The Eve hypothesis, being advanced both by his laboratory and by a group at Emory University, is moving up the date when the races of humanity diverged - and once again Wilson faces resistance. Some anthropologists aren’t happy to see Neanderthal and Peking man removed from our lineage, consigned to dead branches of the family tree. Wilson likes to remind the critics of the last fight. “They’re being dragged slowly along. They’ll eventually come around.”
Homo (genus) Homo is the genus that includes modern humans and their close relatives. Appearance of Homo coincides with the first evidence of stone tools, and thus by definition with the beginning of the Lower Paleolithic.
Humans are constantly on the move, packing up and resettling in different towns, in a neighbouring country, or on the other side of an ocean. Humans have migrated for various reasons since their emergence as a species. Among the natural causes of migration are prolonged droughts, changes in climate or volcanic eruptions that render sizeable areas uninhabitable. People who migrate tend to seek an environment similar to the one they left, but they are influenced by natural barriers, such as large rivers, seas, deserts, and mountain ranges. The belts of steppe, forest, and arctic tundra that stretch from central Europe to the Pacific Ocean encouraged east– west migration of groups situated along their length. Migrations from tropical to temperate areas, or from temperate to tropical areas, have been rare.
Humans are constantly on the move
The Sahara in northern Africa separated the African from the Mediterranean peoples and prevented Egyptian and other cultures from spreading to the south. The mountains of the Himalayas in South Asia cut off the northern approach to the subcontinent of India.
As a consequence of these and similar barriers, certain mountain passes and land bridges became traditional migratory routes. The Sinai Peninsula in northeastern Egypt linked Africa and Asia, the Bosporus region of northwestern Turkey connected Europe and Arabia, and the broad valley between the Altai and Tian Shan mountains of Central Asia enabled Central Asian peoples to sweep westward.
Effect of Migration Stimulates further migration through the displacement of people living in the area. Reduces the numbers of the migrating group because of hardship and warfare. Decimates indigenous populations through warfare with invaders and through vulnerability to new diseases. Alters physical characteristics of ethnic groups through intermarriage. Changes cultural characteristics through adoption of the cultural patterns of peoples encountered. Modifies language.
No one knows for sure exactly when humans first became humans. Scientists use certain characteristics found in fossil evidence (generally the shape of the skull) to differentiate Homo sapiens from earlier species in the genus Homo, such as Homo erectus. Recently, genetic data has also been used to identify early human populations. Since we’re not quite sure when humans evolved in Homo sapiens, we’re also not really sure exactly how or when the earliest humans spread across the rest of the world. Paleoanthropologists have several theories based on the best evidence available. The prevailing theory is the Out of Africa theory. Prehuman hominids probably developed in Africa and spread to Europe and parts of Asia. The first Homo sapiens appeared in Africa roughly 400,000 years ago. This is strongly supported by genetic and fossil data.
With their greater intelligence and organization, Homo sapiens outcompeted other pre-human species for resources.
About 100,000 years ago, they moved north out of Africa into the Middle East, eventually pushing into Europe and Asia. Homo sapiens coexisted with earlier hominids such as Neanderthals. With their greater intelligence and organization, Homo sapiens out-competed other pre-human species for resources, enjoyed greater reproductive success and eventually replaced them. A competing theory suggests that pre-humans that already spread throughout Europe and Asia evolved into Homo sapiens. Separate regional Homo sapiens populations interbred, passing the characteristics of modern humans through the entire human population. This theory accounts for some regional differences seen between different human populations.
What drove those first humans to leave Africa? That’s best explained by examining the forces that continue to drive humans to migrate even today. A population of humans living in a given area faces certain pressures. Those pressures depend on the size of the population, the resources available and the community’s ability to exploit those resources. The most basic population pressure, and the one that likely drove the earliest migrations out of Africa, is food. An area of land can only support a certain population with the food produced there. Modern agricultural techniques and technologies can vastly increase food output, but in the African forests and savannas of 100,000 years ago, humans subsisted by hunting and gathering. If the population grew too large, there wouldn’t be enough meat or fruit to feed everyone. A portion of the population could simply move a few miles away to find new hunting
What drove those first humans to leave Africa?
The most basic population pressure, and the one that likely drove the earliest migrations out of Africa, is food.
grounds. Humans may only have moved a few dozen miles per generation, but over tens of
You can only pack so many humans into a given space. Improvements in
thousands of years, this slow but inexorable migration spread humans throughout the world.
medical and sanitation technology make the exact limit enormously variable, and often far higher than the food limit mentioned above, but at some point the population becomes too large for the area. This can lead to outbreaks of violence or the spread of virulent diseases. A general decline in living conditions leads some people to move elsewhere.
In the short term, weather events can drive a population out of one area. Flooding and severe storms can cause this. Long-term migration patterns have been shaped by climate change. A drought that turns a once-fertile area into a desert will drive the population to find a new home. Changes in sea level can reveal large stretches of coastal land. Massive sections of frozen ocean that occurred during the most recent ice age gave humans access to parts of the world they might not otherwise have reached.
Jared Diamod, the author of “Guns, Germs, and Steel ,“ belives that the availability of potentially domesticable species and a geography conducive to the easy spread of useful species. As it happened, Eurasia enjoyed an edge in both departments. It had far more in the way of domesticable species than any other continent, and its predominantly East-West axis made for easier and faster diffusion of species. These are interesting thoughts, new to historians, and they go a long way towards explaining the formidability of some Eurasian societies vis-a-vis those elsewhere. Diamond’s argument exceeds its limits on another point as well, that of the “tilting axes.” Throughout the book Diamond argues that the East-West axis of Eurasia provided an advantage in the dispersal of useful, mainly domesticated, plants and animals. With respect to the lengths of days and the importance thereof for flowering plants, the argument makes fine sense. Maize’s spread northward from Mexico was, Diamond persuasively argues, slowed by the necessity of genetic adaptation to different day lengths at different latitudes. Maize could spread much more easily East-West than it could North-South. But with respect to animals the argument must be made in more general climatic and ecological terms, and here it gets weaker.
domesticated, plants and animals.
Eurasia’s East-West axis could not have been much help in the spread of cattle or goats. Its extreme variety of climatic conditions, its high mountains, deserts, and tropical forests posed a considerable challenge for the spread of most animals (and I should think, plants). From the Gulf Stream-induced equability of western Europe, to the continental climate extremes of Kazakhstan, to the monsoon rhythms of Korea, temperature and moisture regimes show tremendous variation. A given line of latitude within Eurasia might embrace conditions as diverse as those of Shanghai, Lhasa, Delhi, Basra, and Marrakesh, all of which are very close to thirty degrees north (North Africa counts for most of Diamond’s purposes as part of Eurasia).
Pottery, rock art and animal remains that suggest pastoralists herders who migrated to new pasture with their flocks - first tended sheep and cattle in southern Africa around 2,000 years ago.
Beyond this, since North Africa counts as part of Eurasia, then Africa deserves an East-West axis like Eurasia’s, because it is farther from Dakar to Cape Gardafui than it is from the Cape of Good Hope to the Sahara. And Australia, which does not get an axis on the map, extends further East-West than North-South. In Australia, I should think rainfall isohyets would correspond better to the migration history of plants and animals than lines of latitude and longitude. All this, casts some doubt on the explanatory power of the axis argument. Indeed, the successful spread of crops and livestock (not to mention the writing, wheels and other inventions that Diamond mentions in this argument) is surely determined in large part by factors
East-West axis presented similar climatic, geographic, and disease conditions to migrants and no insuperable barriers.
other than geography, and the role of geography is much more complex than the axes suggest. The role of other geographical factors I alluded to in reference to Eurasia. But the spread of useful species was usually a conscious act (weeds were different). They could not, of course, flourish where ecological conditions did not permit, but where they went when was largely a human affair, determined by trade links, migration routes, and happenstance.
Coffee, an Ethiopian native, eventually made its greatest impact in southern Brazil, not at Ethiopian latitudes within Africa. Cattle domestication spread from its point of origin (in southwest Asia) to South Africa and Sweden, flourishing in between in circumstances as diverse as Sudan’s and Switzerland’s. Along the East-West axis of Eurasia, cattle became important in Europe, fundamental in India, yet inconsequential in China. This is not because Chinese environmental conditions were inhospitable to cattle, but because Chinese social and economic conditions were. The diffusion of cattle as of AD 1000 was along a North-South axis more than an East-West one, partly because cattle can cope with both heat and cold, but also because cattle-raising fit in with the ideological, cultural, social, and economic systems of some societies better than others, regardless of geography. Human The diffusion of food production was facilitated in Eurasia because its predominantly East-West axis presented similar climatic, geographic, and disease conditions to migrants and no insuperable barriers. In contrast, the diffusion in the predominantly N-S axis in the Americans, Africa, and New Guinea/Australia was slowed by the greater variation in climate, deserts, diseases (e.g., trypanosomes), nonarable lands, jungles (e.g., Panama), etc. It was Eurasia that had “amber fields of grain and spacious skies”, not the New World. Diffusion rates varied from 0.7 miles/year out of SW Asia to 0.3 mile/year in the eastern US. The lack of adaptation of the domesticates to these widely ranging climatic and other differences was a major factor in slowing diffusion in the New World.
—Jared Diamond
Expansions of crops, livestock, and even people tended to occur more rapidly along east–west axes than along north–south axes.
It was easier for domestic plants and animals (later, technology like wheels, writing) to spread East-West in Eurasia than North- South in Americas. Some crops (lima beans, common beans, chili peppers) domesticated independently in both S. America and Meso America due to slow spread. Most crops in Eurasia domesticated only once. Rapid spread preempted same or similar domestication. Fertile Crescent crops spread to Egypt, N. Africa, Europe, India and eventually to China. East-West spread of plants, animals easier due to same day-length, similar seasonal variations. By contrast, spread of these crops stopped past Sahara due to tropical climate, and thus didn’t reach temperate S. Africa until colonists came. Tropical crops spread West to East in Africa with Bantu culture, but did not cross to S. Africa due to climate. Distance between cool highlands of Mexico and Andes was 1,200 miles but separated by low hot tropical region. Thus, no exchange of crops, animals, wheel. Only maize spread. It took 2,000 years for maize to cross 700 miles of desert to reach U.S.A. It took another 1000 years for maize to adapt to U.S.A. climate to be productive. Geographic barriers like mountains and deserts also slow spread of crops East-West. Agriculture spread from U.S.A. southeast to southwest slowed by dry Texas and southern great plains. Amber waves of grain did not stretch from sea to sea in N. America, but did in Eurasia.
Fertile Cresent Advantages
Mediterranean climate with diversity of species. High percentage of annual plants. 32 of 56 grass species grow here. Diversity of species (big animals) to be domesticated.
Domesticated Plants Several domesticable plants had large ranges, but domesticated only in one place. Why not in others? Domestication required settling down, and had to be worth it with several plants domesticated, not just one.
There are 200,000 species of plants Only a dozen account for 80% of worlds production: Wheat, corn, rice, barley, sorghum, soybean, potato, sweet potato, sugar cane, sugar beet, banana.
Fertile Crescent Attributes; mediterranean climate; abundant wild
All of these domesticated thousands of years ago.
stands of wheat that needed little change to be domesticated; hunters/
No new plants domesticated in modern times
gatherers settled down before living off grain; and high percentage of
Domesticated Animals
self pollinating plants, are the important factors
Of the 14 large (over 100 lb) successful domesticated animal species in the world. Of 148 large herbivorous or omnivorous species in the world, Eurasia had 72; Africa 51; Americas 24; and Australia had 1. When the big 5 Eurasian domesticates (Cow, sheep goat, pig, horse) were introduced into Africa and the Americas they were readily adopted. All peoples have experience taming wild animals, keeping pets. But not all tamed animals can be domesticated. All major animal domestication occurred between 8,500-2,500 B.C. with almost none since then. Those of the 148 possible species capable of being domesticated were domesticated. Some species like cows, dogs, pigs independently domesticated in different parts of the world. These animals were well suited for domestication. Attempts to domesticate eland, elk, moose, musk ox, zebra, American Bison are only marginally successful.
Mt DNA Mitochondria DNA (Mt DNA) are normally inherited exclusively, nearly unchanged, from the mother. The fact that Mt DNA is maternally inherited enables researchers to trace maternal lineage far back in time.
Theresearchconfirmsthe“OutOfAfrica”hypothesisthat all modern humans stem from a single group of Homo sapiens who emigrated from Africa 2,000 generations
All modern humans have a common ancestry
ago and spread throughout Eurasia over thousands of years. These settlers replaced other early humans, rather than interbreeding .
Academics analysed the mitochondrial DNA (mtDNA) and Y chromosome DNA of Aboriginal Australians and Melanesians from New Guinea. This data was compared with the various DNA patterns associated with early humans. The research was an international effort, with researchers from Tartu in Estonia, Oxford, and Stanford in California all contributing key data and expertise. The results showed that both the Aborigines and Melanesians share the genetic features that have been linked to the exodus of modern humans from Africa 50,000 years ago.
Reserchers have produced new DNA evidence that confirms the theory that all modern humans have a common ancestry.
Until now, one of the main reasons for doubting the “Out Of Africa” theory was the existence of inconsistent evidence in Australia. The skeletal and tool remains that have been found there are strikingly different from those elsewhere on the “coastal expressway”– the route through South Asia taken by the early settlers.
Some scholars argue that these discrepancies exist either because the early colonists interbred with the local Homo erectus population, or because there was a subsequent, secondary migration from Africa. Both explanations would undermine the theory of a single, common origin for modern-day humans. But in the latest research there was no evidence of a genetic inheritance from Homo erectus, indicating that the settlers did not mix and that these people therefore share the same direct ancestry as the other Eurasian peoples.
Geneticist Dr Peter Forster, who led the research, commented: “Although it’s been speculated that the populations of Australia and New Guinea came from the same ancestors, the fossil record differs so significantly it has been difficult to prove. For the first time, this evidence gives us a genetic link showing that the Australian Aboriginal and New Guinean populations are descended directly from the same specific group of people who emerged from the African migration.” At the time of the migration, 50,000 years ago, Australia and New Guinea were joined by a land bridge and the region was also only separated from the main Eurasian land mass by narrow straits such as Wallace’s Line in Indonesia. The land bridge was submerged about 8,000 years ago. The new study also explains why the fossil and archaeological record in Australia is so different to that found elsewhere even though the genetic record shows no evidence of interbreeding with Homo erectus, and indicates a single Palaeolithic colonisation event. The DNA patterns of the Australian and Melanesian populations show that the population evolved in relative isolation. The two groups also share certain genetic characteristics that are not found beyond Melanesia. This would suggest that there was very little gene flow into Australia after the original migration. Dr Toomas Kivisild, from the Cambridge University Department of Biological Anthropology, who co-authored the report, commented that, “The evidence points to relative isolation after the initial arrival of the group, which would mean any significant developments in skeletal form and tool useage were not influenced by outside sources. “There was probably a minor secondary gene flow into Australia while the land bridge from New Guinea was still open, but once it was submerged the population was apparently isolated for thousands of years. The differences in the archaeological record are probably the result of this, rather than any secondary migration or interbreeding.”
Australia’s aboriginal population sprang from the same small group of colonists, along with their New Guinean neighbours.
Homo sapiens originated in Africa 150,000 years ago and began to migrate 55,000 to 60,000 years ago. It is thought he arrived in Australia around 45,000 years before present (BP). Australia was, at the time, already colonised by homo erectus. The eastern migration route towards Australia is referred to as the “coastal express” route, due to the comparatively rapid progress made by those who used it. This dispersal, from Africa to Australia through Arabia, Asia and the Malay peninsula, could have occurred at a rate of 1km per year. The archaeological data also indicates an intensification of the density and complexity of different stone tools in Australia during the Holocene period (beginning around 10,000 years BP), in particular the emergence of backed-blade stone technology. The first dingos arrived at around the
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same time, and it is thought both were brought to the continent by new human arrivals – leading to theories of a secondary migration that has resulted in disputes regarding the single point of origin theory.
Australia’s archaeological record provides several apparent inconsistencies with the “Out Of Africa” theory. In particular, the earliest known Australian skeletons, from Lake Mungo, are relatively slender and gracile in form, whereas younger skeletal finds are much more robust. This robustness, which remains, for example, in the brow ridge structure of modern Aborigines, would suggest either interbreeding between homo sapiens and homo erectus or multiple migrations into Australia, followed by interbreeding.
—Spencer Wells
In 1758, Carl Linnaeus, the father of taxonomy, coined the term Homo Sapie-ns in his book Systema Naturae one of the first records of man’s quest for his roots. The fascination continued throughout the centuries, which was propelled by Darwin’s theories, technological advances and increased funding. In 1963, the concept of races or sub-species within the human race was refined by Carleton Coon in The Origin of Races. And now, gene mapping and tracing of roots has been elevated to a whole new level, with the Genographic Project, a five-year research jointly being conducted by National Geographic Society, IBM Corp. and the Waitt Family Foundation. This path-breaking project is unravelling the story of our origins through 100,000 DNA samples. Dr Spencer Wells, the National Geographic Explorer in Residence and Population Geneticist, who developed the concept and now provides overall coordination, says, Genographics is a concerted scientific effort to answer the basic question where do we all come from?
through reconstructing the family tree We delve into the DNA composition of individuals to arrive at the answer to
We delve into the DNA composition of individuals to arrive at the answer to this question, by reconstructing the family tree of everyone alive today.
this question, by reconstructing the family tree of everyone alive today. Dr Wells was in town to deliver a lecture on Deep Ancestry Inside the Genographic Project at the Georgetown University at Education City. He speaks at great length on the various components of the project, the partners, the findings so far, the sampling structure, indigenous populations, what the project is doing with them, how the project findings will help humanity at large and the ethical issues involved.
According to Dr Wells, there are approximately 50 mutations in our genetic structure, which create variations in the gene pool of every generation, which in turn gets passed on to the next. DNA (deoxyribonucleic acid) is a long informational molecule and the sequence of its components provides information about the origins and evolution of human beings.
The DNA samples are being collected by voluntary public participation. This unprecedented effort, led by National Geographic which is distributing and selling the Participation Kits, will map humanity’s genetic journey through the ages while helping us better understand our own history. The findings will also help in understanding how, despite our diverse appearances, we all share common origins and how we went about populating the planet. The story that we are telling from the findings so far suggest that we, homo sapiens, originated as a species in Africa some couple of thousands of years ago. It is a common stock that gave rise to the entire human race. We are all members of an extended African family and started to leave that place some time around 60, 000 years ago to populate the entire world which is roughly 2000 generations, a blink of an eye in evolutionary science. On the detailed structure of the project, Wells adds, the entire model of the project is based on cooperation between the scientists who are participating in the project and the tribal elders. The project involves extensive travels to enable the researchers reach the local indigenous population, explaining what we are looking at and eliciting their interest in the project and explaining what is involved in participating. The route we are taking to collect DNA is through blood samples or cheek swabs. We then extract the DNA, purify it and then take what is called genetic markers, which are random but tiny little changes in the DNA that occur in them and are passed on from generation to generation. These are markers of descent, which then are mapped against the family trees. This is the core of the project and we have three components. The first Field Research is what we are doing with indigenous people, which is any group of people who have lived in one place for the past 500 years or more and have a connection with the place that they have lived. The tenure varies it could be 500 years for some locations or in others it could extend to 100,000 years in the case of Africa or 50, 000 years in the case of Southern India or Australia. It could be a tribe, a village, any population combine that has not been affected by the mass migrations all over that were necessitated with the Industrial Revolution. We are studying 100,000 such samples. The field researchers are being led by a group of population geneticists who study genetic variations and there are 10 regions across the globe where the research is on. The second is Public Participation and Communication, which is the story of all of us and thus we wanted to encourage wide public participation, even outside indigenous populations. The participation of the project helped financing the third component of the project -- the Legacy Project that will help us in giving something tangible back to these indigenous people. So far we have raised $2.2 million and this money is being utilised for the educational and cultural initiatives that have been organized by these indigenous people themselves, like language or crafts preservation.
nucleus
cytoplasm
chromosomes mitochondria
Human Cell MtDNA is not contained in the nucleus but is located in the cytoplasm of the cell. All of the mtDNA in the cells of a person’s body are copies of his or her mother’s mtDNA. A son recieves his mtDNA from his mother, but does not pass it to his offspring.
In 1987, three scientists announced in the journal Nature that they had found a common ancestor to us all, a woman who lived in Africa 200,000 years ago. She was given the name “Eve.” The “Eve” in question was actually the most recent common ancestor through matrilineal descent of all humans living today. That is, all people alive today can trace some of their genetic heritage through their mothers back to this one woman.
every single cell contains our entire genetic information
The scientists hypothesized this ancient woman’s existence by looking within the cells of living people and analyzing short loops of genetic code. Scientists have used DNA to trace the evolution and migration of human species, including when the common ancestor to modern humans lived—though there has been considerable debate over the validity of the findings.
The scientists hypothesized this ancient woman’s existence by looking within the cells of living people and analyzing short loops of genetic code.
The human body consists of 60 thousand billion cells (eg white blood cells, muscle cells, or cheek cells) of which nearly every single cell contains our entire genetic information, the DNA. Inside the cell, DNA is found inside the nucleus (chromosomal DNA, consisting of autosomal DNA, X chromosomal DNA and Y chromosomal DNA) and outside the nucleus (mitochondrial DNA).
Our autosomal DNA is inherited from both parents. Ychromosomal DNA (Y-DNA) is inherited only from father to son, and mitochondrial DNA (mtDNA), from our mother.
After the process of fertilization, the sperms’ mitochondria die away, and the embryo is only left with maternal mitochondria. We share the same mtDNA as our brothers and sisters, but not our fathers. MtDNA is passed down nearly unchanged from generation to generation. So we share the same mtDNA-type as our mother, our maternal grandmother,
Mitochondrial
our maternal great-grandmother and so on. In fact the exact same mtDNA code will track our direct genetic line back until the point at which a natural mutation in the mtDNA code occurred - on average about every 10,000 years. The logical extension of this is that we all ultimately trace back to one woman who lived around 150,000 years ago, who is commonly referred to as Mitochondrial Eve. Since that time, Mitochondrial Eve’s descendants have gradually populated the entire globe, with the original founder group spreading geographically and branching genetically in the course of the millennia, leaving genetic footprints - or mutations in their mtDNA - at regular intervals wherever they went. These prehistoric branching events can be read in the ancient mutations of our mtDNA like in a history book. mtDNA has now been used to trace back through all of these natural mutations to the origins of all modern human existence to a woman known poetically as ‘Mitochondrial Eve’, who lived around 150,000 years ago. ‘Mitochondrial Eve’ is most recent common ancestor of all humans alive on Earth today with respect to our matrilineal descent. Note that this does not necessarily mean that she was the only woman alive at that time. Presumably there were other females alive at that time, but her lineage is the only female lineage to have survived through to the modern day. Since then, as people have migrated across and out of Africa, their mtDNA has changed slightly owing to very occasional mutations in the genetic structure, offering us the wealth of different mtDNA types now.
...the exact same mtDNA code will track our direct genetic line back until the point at which a natural mutation in the mtDNA code occurred.
The concept of ‘Mitochondrial Eve’ is in some sense a purely mathematical fact. Consider the number of all women living on earth today, ‘A’. Now consider the number of the mothers of all women living on earth today, ‘B’. Obviously, B is either the same size or less than A. As you go back through the generations, B reduces, ultimately to one woman. That woman is popularly referred to as Mitochondrial Eve.
Y chromosome Y chromosome is the sexdetermining chromosome males. Y chromosome is passed down exclusively from father to son, all human Y chromosomes today trace back to a single prehistoric father, “Y chromosomal Adam”.
Y chromosomal
Because the Y chromosome is passed down exclusively from father to son, all human Y chromosomes today trace back to a single prehistoric father, “Y chromosomal Adam”, whose time we can date to more than 100,000 years ago using statistical methods.
Just like mtDNA, the original Y chromosome has mutated its DNA naturally over the generations and these new Y types have settled in various parts of the world in prehistory. By determining your present Y-type and searching the worldwide Y database, Cambridge DNA Services can give you a good idea where in the world your father’s lineage is generally found today. Additionally, family researchers (genealogists) who wish to know whether two people with the same surname are related, are increasingly using Y chromosomal tests. This is possible because in many cultures, family names or surnames are passed down by the father just like the Y chromosome. In such cases, two Y tests are needed: one Y test for oneself, and Y test for the person with the same surname who is suspected to be related. All that is then needed is to compare whether the two Y results are identical. The y-chromosome is a good candidate for population studies such as this because it doesn’t recombine as other parts of the genome do (each parent contributes half of a child’s DNA, which join together to form a new genetic combination). Thus, the y-chromosome is passed on as a chunk of DNA from father to son, basically unchanged through generations except for random mutations.These random mutations, which can happen naturally and be harmless, are called markers. Once a marker has been identified, geneticists can go back in time and trace it to the point at which it first occurred, which would be the most recent common ancestor.
No historical record exists that tracks the migratory patterns of the earliest humans. Scientists piece together the story of human migration by examining the tools, art and burial sites they left behind and by tracing genetic patterns. They accomplish that using the DNA markers by looking at mitochondrial DNA (mtDNA), and Y Chromosome.
The DNA is unchanged through generations except for random mutations. These random mutations, which can happen naturally and be harmless, are called markers. Once a marker has been identified, geneticists can go back in time and trace it to the point at which it first occurred, which would be the most recent common ancestor.
Geneticists have found fragments of DNA in the Khoisan ethnic group, of which the Kung San people, sometimes called the Bushmen of the Kalahari, are one tribe, that appear to date back to the very first human beings.
With the benefit of genetics, and mitochondrial DNA, we are now able to look at the footprints that our earliest of ancestors left. Subtle, natural mutations in mitochondrial DNA have enabled scientists to analyse the development of the world’s populations. Soon after the appearance of Mitochondrial Eve around 150,000 years ago, an early expansion of modern humans populated much of Africa, around 100,000 years ago. The incredible story of the peopling of the world is told through a combination of genetics and archaeology. The group of mtDNA sequences from this first expansion can still be found today, particularly in the KhoiSan of Southern Africa and the West pygmies of Central Africa. These earliest groups of mtDNA sequences - or haplogroups - are known by scientists as ‘L1’ and ‘L0’, and all subsequent groups are also known by a letter. Haplogroups are major branches on the family tree of Homo Sapiens. These haplogroup branches characterize the early migrations of population groups. As a result, haplogroups are usually associated with a geographic region. If haplogroups are the branches of the tree then the haplotypes represent the leaves of the tree. All of the haplotypes that belong to a particular haplogroup are leaves on the same branch. Both mtDNA and Y-DNA tests provide haplogroup information, but remember that the haplogroups nomenclature are different for each. About 60,000 years ago a founder group moved out of Africa and their descendants, through the natural process of mutation, formed the haplogroups M and N. These groups in turn gained a foothold during the Ice Age in Asia, Australia and parts of Europe and evolved their own specific types. So, for example, Europe is populated by the haplogroups H, I, J, K, T, U, V, W and X; Asia by A, B, C, D, E, F, G, M, and Y; the Americas by an Asian branch with A, B, C, D and X ; Papua New Guinea by P and Q; and Australia by further M and N types.
Haplogroups were assigned letters of the alphabet before the complete analysis was done which means that the specific letter assignment itself is meaningless.
Genealogist has tracked the routes and timing of migration, Based on a synthesis of the mtDNA and Y chromosome evidence with archaeology, climatology and fossil study.
destination
settlement
discovery
160,000-135,000
Herto Man
Four groups travelled as hunter/gatherers south to the Cape of Good Hope, south-west to the Ivory Coast, carrying the first generation of mtDNA gene types ‘L1’
Reconstructive Eve
135,000-115,000 125,000 years ago, a group travelled across a green Sahara through the open northern gate, up the Nile to the Levant. 1st EXIT.
115,000-90,000 The branch that reached the Levant died out approximately 90,000 years ago. A global freeze - up turned this area and north Africa into an extreme desert. This regieon was later reoccupied by Neanderthal Man.
Gates of Grief
90,000-85,000 85,000 years ago a group crossed the mouth of the Red Sea-the Gates of Grief-prior to travelling along the southern coast of the Arabian Peninsula toward India. All non-African people are descended from this group.
85,000-75,000 From Sri Lanka they continued along the Indian Ocean coast to western Indonesia, then a landmass attached to Asia. Still following the coast they moved around Borneo to South China.
Blombos
74,000 Mt Toba Kota Tampan
Eruption of Mt. Toba, Sumarta, causing a 6 year nuclear winter and instant 1000 years ice-age with a dramatic population crash, to less than 10,000 adults. Volcanic ash from the eruption up to 5m deep covered India & Pakistan
74,000 -65,000 After the devastation of the Indian subcontinent, repopulation took place. Groups crossed by boat from Timor into Australia and also from Borneo into New Guinea. There was intense cold in the Lower Pleniglacial in the north.
65,000-52,000 Dramatic warming of the climate 52,000 years ago meant groups were finally able to move north up the Fertile Crescent returning to the Levant. From there they moved into Europe via the Bosporus from 50,000 years ago.
52,000-45,000 Mini Ice Age. Aurignacian Upper Palaeolithic culture moved from Turkey into Bulgaria, Europe. The new style of stone tools moved up the Danube into Hungary then Austria.
45,000-40,000
Haua Fteah
Groups from the east Asian coast moved west through the centeral Asia steppes towards Northeast Asia. From Pakistan they moved into Centeral Asia, and from Indo-China through Tibet into the Quing-hai Plateau.
Chauvet
40,000-22,000 Meadowcroft
Colonization
Centeral Asians moed west towards eastern Europe, North into the Arctic Circle and joined East Asians to start the spread nto north-east Eurasia.This period saw the birth of spectacular works of art, as in the Chauvet cave in Frnace.. Ancestors of the Native Americans who crossed the Bering land bridge connecting Siberia to Alaska, either passed through the ice corridor reaching Meadowcroft before the LGM, or took the coastal route.
22,000-19,000 During the last Ice Age, Nothern Europe, Asia and North America were de-populated, with isolated surviving groups locked in refuges. In North America the ice Corridor closed and the coastal route froze.
19,000-15,000 The last Glacial Maximum18,000 years ago. In North America, south of the ice, groups continued to develop diversity in language, culture and genes as they crosses into South America. Austrailian rock art-Bradshow Paintings
Bradshaw Paintings
15,000-10,000
Clovis
Taima Taima
Indian Rock Art
Monte Verde Luzia
Continued amelioration of the global climate. Coastal route recommenced. Monte Verde, Chile-human habitation; radio-carbon dating from 11,790 to 13,565 yeasr ago. Stone tools such as flakes and cobbles were excavated. Recoccupatio n of North America 12,500 years ago from south of the ice going north. In the sub-Arc tic 11,500 years ago people moved out from the Beringean refuge to become the Eskimo, Aleuts and Na-Dene speakers.
10,000-80,000 Dabous Carving
The final collapse of the Ice Age heralded the dawn of agriculture. The Sahara was grassland, as implied by the life-size giraffe petroglyphs in Niger. Reconlonisation of Britain and Scandinavia.