CRISPR stands for “clustered regularly interspaced short palindromic repeats” – an acronym which seems complicated but ultimately boils down to an easily recognisable portion of DNA. Cas9 refers to an “endonuclease”: a structure in cells capable of easily cutting both DNA strands. Together they form a system that allows precise targeting of genes for modification and editing. Cas9 was developed into a mutant form by a researcher named Cong, and colleagues, which was even more precise by cutting one DNA strand. The system of editing itself exists naturally as a defence mechanism in the bacterial species Streptococcus pyogenes; responsible for some skin infections, amongst others.
CRISPR/Cas9 has already seen a myriad of applications in research for potential solutions to threatening diseases. Scientists have taken systems unique to a species of bacterium and applied it to an absurd variety of organisms. Included in this are monkeys, zebrafish, pigs, rats, mice, fruitflies, roundworms, and humans. For example, it was used to fix the gene responsible for cystic fibrosis in human intestinal stem cells by a team led by Schwank in 2013. This holds promise for a future therapy in itself.
These discoveries hold incredible significance. The versatility for targeting different genes means that CRISPR/cas9 could help develop an incredible range of new therapies. It represents some of the ultimate aims and goals of science: taking and re-working natural systems for the purpose of solving other human issues. In this case, these natural systems have even been appropriated from an organism that can be harmful to humans.
Of course, ethicists have discussed the possibility of genetic modification and editing becoming employed in use of less noble pursuits; such as the classic example of the “designer baby”. CRISPR/cas9 is not remotely within the bounds of editing the qualities of an embryo or foetus. To my personal knowledge, no studies have been conducted on human egg or sperm cells with the CRISPR system, and certainly any attempt to would be met with appropriate scepticism and regulation by research ethics boards.
At the current level of research, genetic modification is not some game of ‘The Sims’ with real human life. Any idea like this is most likely the work of science fiction or speculation. For this reason, genetic modification should indeed be embraced. Whilst a close eye should always be kept on developments (in case they ever be utilised with bad intention), genetic modification holds enormous potential for future treatments, and the CRISPR/cas9 system could very well represent the forefront of this. It no longer seems to ridiculous to imagine a world devoid of disorders such as cystic fibrosis; a world where such achievements were attributable to these studies conducted in the last five years.
Mentioned Today in Headcandy:
Cong et al – Multiplex Genome Engineering Using CRISPR/Cas Systems