Moore's Law and Genetics: How CRISPR is Revolutionizing the World
By Ryan LeePublished March 11, 2015By Ryan Lee, 3/11/15
Genetic engineering is now in its fourth decade of life and has come an awful long way in that relatively short span of time. In 1973, the use of restriction enzymes allowed for the very first recombinant DNA (rDNA) to be inserted by humans into bacteria. It took over 20 years between that first discovery and the very first transgenic crops to hit the market. Since the 90's, genetically modified crops have grown from a tiny market niche to become the most widely and rapidly adopted agricultural technology in history. Today, dozens of new organisms with purposes as various as improving nutrition or reducing hangovers are currently coming down the pipeline. Indeed, genetic modification of organisms with various rDNA technologies has become ubiquitous in our society. Yet despite the considerable power of genetic engineering as we know it, the recently developed technique known as CRISPR/Cas9 is revolutionizing the way genetic engineering is done. This technology has the potential not only to reduce the costs and the amount of time required of genetic engineering, but also to increase the precision with which the genes can be modified.
CRISPR stands for clustered regularly interspaced short palindromic repeats, and Cas9 is an abbreviation for CRISPR associated protein 9. In 2005, it was discovered that the short repeating sequences which had been observed in the genomes of bacteria were somehow related to the bacterial immune system. It turned out that bacteria can snip sequences of DNA out of pathogens and store them in their own genome, providing instructions for the Cas9 protein to use to identify and destroy invading DNA. A few years later, Jennifer Doudna and Emmanuelle Charpentier figured out how to use this mechanism to perform direct edits to the genes of essentially any target organism. Thus, a new era dawned for genetic engineering. What had before taken years of trial and error and endless repetition to achieve could now be accomplished quickly, efficiently and precisely.
Now, a new application of CRISPR technology described in this week's Science magazine has done what has never been done before and has turned Mendelian genetics on its head. This technique, known as mutagenic chain reaction or gene drive, has enormous potential. In short, the researchers Valentino Gantz and Ethan Bier created a mutation on one chromosome which transcribed itself onto the homologous chromosome. Those chromosomes then in turn edit the embryonic chromosomes of any other parent with which the mutant is crossed. What this means is that a scientist can now take a heterozygous mutation and turn it into a homozygous one with the process repeating autonomously in subsequent generations.
Though this research is brand new, it is not hard to see the potential impacts of this technology. Imagine a future in which the malaria parasite could no longer colonize mosquitos, and thereby could no longer infect humans. We could wipe out malaria without the need for insecticides or expensive drugs. Of course, what could be a Promethean gift could also prove to be a Pandora's Box. It is possible that other genes in the genome could be incorporated into the gene cassette and spread throughout a population. Such an effect would have unforeseeable consequences for genetic diversity in that population or species. Deleterious mutations in the cassette may also occur, possibly negatively impacting the population as well. As such, George Church of Harvard Medical School has called the research "a step too far".
Just as Moore's law predicted the exponential growth of computing power, can we now begin to see an era of exponential advances in gene editing and engineering on the horizon? Certainly, CRISPR has already begun to demonstrate that possibility by simplifying and accelerating the process. But, despite the parallels one could draw, genes are not computers; they are the vital, universal, intimate instructions for the processes of life itself. The emerging generation of gene editing technologies has the potential to fundamentally transform life itself, and we must think very carefully about what this implies. It is this author's opinion that we have now truly reached an event horizon beyond which lies a future we cannot yet even begin to imagine.