Crispr - The Chemistry of Gene - Editing

By Josh Nicks

Or Chipr, if you’re based in the US...

The 2020 Nobel prize in chemistry has been awarded to Emmanuelle Charpentier and Jennifer Doudna, for their discovery of the Crispr-Cas9 genome editing technique. In short, this technique allows scientists to reprogram a living organisms genetic code. Its relative ease of use and low cost compared to other editing techniques have seen the field grow exponentially. The potential impacts of Crispr span almost every aspect of our lives, from pharmaceuticals and therapeutics, to agriculture and nutrition. However alongside Crispr’s huge potential, lies a fair amount of controversy. This article examines Charpentier and Doudna’s pioneering research, the way it works, and how it could, and by all means already has managed to, change our lives.

How does it work? Crispr is actually an acronym that stands for “cluster regularly interspaced short palindromic repeats”. This refers to discrete genetic sequences found in the genomes of bacteria. Every Crispr sequence becomes transcribed into RNA sequences, which target the DNA of a virus, as found by Charpentier. Doudna discovered that these sequences contain cas genes, which code for the cas enzymes that perform the DNA-cutting These enzymes and the guide-RNA work together to cut the viral DNA.

Jennifer Doudna (left) and Emmanuelle Charpentier (right) are the first pair of women to share the Nobel chemistry prize .

Charpentier and Doudna exploited this very system - by designing a guide RNA sequence that matches a genomic target sequence. The RNA sequence and Cas9 enzyme (hence the name, Crispr-Cas9), slice the DNA where targeted, allowing for immensely precise editing of the genome sequence.

Much like other Nobel prizes, this work doesn’t seem to be free of controversy. As a fairly new technique, Crispr has not yet been perfected. Some research has demonstrated off-target cuts, in which the tool has sliced DNA at more than just the desired areas. Obviously this could have disastrous complications, and a remedy to this remains one of the main areas of Crispr research. In fact, Doudna, Charpentier, and others have suggested a suspension on the editing of human germline cells, stating we need to know more about potential consequences.

Despite this controversy, the dynamic potential of Crispr as a tool for engineering life is clear. So many issues could potentially be wiped away, if this technique is perfected. Scientists could correct the genetic errors that cause disease, eradicating issues such as Huntington’s and hypertrophic cardio-myopathy.

Gene editing also extends to agricultural developments. It has already been used to increase the yield of tomato plants, by altering the genes

that govern tomato size, shape, and branching architecture.

Crispr even has the potential to resurrect species. Harvard geneticist George Church has claimed he and his team are close to developing an embryo for an elephant-mammoth hybrid. Crispr’s strengths and potential are clear for all to see, and it is only a matter of time until Charpentier and

Doudna’s work is an everyday matter.

1. bit.ly/328yuYd 2. Futurism.com/crispr-geneticengineering-change-world

Editing the branching structure genes of tomato plants can dramatically increase yields.