Rewriting the code of life
Advances in CRISPR-Cas9 technology are this year’s greatest biological triumph, argues Andre Lo
CRISPR genome editing techniques – the most noteworthy being CRISPR-Cas9 – have been setting the scientific community abuzz in recent years. 2017, however, has seen some of the most exciting implementations of the technology: from reviving the possibility of cross-species organ transplantation to pioneering the use of these molecular tools in manipulating the genes of viable human embryos. Yet, since scientists hypothesised its potential for precise and efficient genome editing, manipulating DNA has perhaps become too easy.
“As genetic engineering becomes more accessible, we increasingly need means to regulate its use”
The gene-editors in question are adapted from a bacterial defence mechanism known as the ‘CRISPR-Cas’ system, which provides a targeted DNA cutting mechanism. This then triggers DNA repair systems, theoretically underpinning an elegant ‘cut-and-paste’ technology for genomes. And CRISPR-Cas technologies have proven much quicker and cheaper than previous genome editing methods – James Harber, a CRISPR-Cas9 expert, states that the technology can used to edit genes for “as little as $30”; this compares favourably to previous tools, “which cost $5,000 or more to order”. It is no wonder, therefore, that the field of genetics has been propelled to new heights.
Testament to this boom in genetics research, the world has seen endless application of CRISPR technology. This year, Lichun Tang and colleagues were the first to test CRISPR genome editing on viable human embryos, attempting to correct DNA mutations associated with blood disorders such as anaemias. Further, a research team including CRISPR pioneer George Church successfully used CRISPR-Cas9 to inactivate the viral genes scattered within a normal porcine genome, which have been a concern for contamination in transplanting organs from pigs into humans. For 2018, clinical trials are being planned that involve direct introduction of the molecular scissors into humans - versus the as yet favoured methodology of extracting cells, editing their code, and reintroducing them into the host.
Nevertheless, while CRISPR technologies open up unprecedented possibilities in the field of genetics, there are very real dangers to be considered. Most obviously, despite the progress of 2017, the technology is still immature. Scientists are working out ways to limit CRISPR techniques from creating potentially hazardous off-target cuts, but they are not there yet, despite some progress. Moreover, when it comes to human applications in a clinical context, that differences in an individual’s genome can alter the efficacy and safety of the CRISPR-Cas9 tool, thus rendering its use too precarious to be conceivable.
Even if we overcome such limitations, how might we prevent mishandling of this technology? Regulation of gene editing technologies such as CRISPR is quite heterogenous. For example, unlike the US and China, genetic manipulation of human embryos is banned in Canada. Further, CRISPR research may be required to pass ethics reviews, yet ‘biohackers’ such as Josiah Zayner have openly flouted these stipulations. So, what is there to stop a crazed dictator from hypothetically realising a version of Hitler’s Lebensborn program and creating an ‘ideal’ race? Or how could we foil the possible rise of black market CRISPR treatments? Combined with recent breakthroughs in ectogenesis, the dystopian future described by Aldous Huxley’s Brave New World may no longer be too distant a possibility.
2017 has been a great year for CRISPR genome editing. Yet as genetic engineering becomes more accessible, we increasingly need means to regulate its use. CRISPR technologies will continue to advance scientific knowledge and practice, but this cannot be at the expense of ethical behaviour
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