The Death of Evolution at the Hands of CRISPR-Cas9

The unpredictability of evolution has meant every species has succumbed to the forces of genetic drift or environmental stochasticitiy. CRISPR-Cas9 may finally remove the element of chance in the complex process. This revolutionary modification tool utilises a guide RNA to direct the Cas9 enzyme to a specific location in the DNA sequence, where a gene is either inserted, deleted or modified. CRISPR-Cas9 can be used to develop treatments for genetic disorders or create disease resistant crops. Its uses are not limited to the practical though, with many theorising methods to enhance intelligence, reverse extinction events, or entirely disrupt the fundamentals of evolution. Survival of the fittest. Though Social Darwinists have twisted the values of this theory to justify their wildly controversial views, at its core, the process by which advantageous traits become more common in a population over generations is driven solely by environmental pressures and random mutations. Until now. With the introduction of CRISPR-Cas9, there comes a potential end to traditional natural selection. Selective pressures that have historically dictated evolution will become secondary to human choice. In 2022, CRISPR was used to modify CAR-T cells to treat teenagers with relapsed T-cell acute lymphoblastic leukaemia – a blood cancer that responded to neither chemotherapy nor bone marrow transplants. By modifying healthy T-cells to target the CD7 marking and destroy every T-cell in the patient’s bodies, the immune system can then be entirely rebuilt. Though there are other examples of success stories, the long-term impact of human-directed genetic modification must be considered when entertaining the possibilities of CRISPR-Cas9. What actually will happen when we override evolution? Eugenics. The chilling term refers to the immoral practice of attempting to improve the genetic quality of human populations. Eugenics gained popularity with contentious notion that selective breeding could eliminate undesirable traits and enhance desirable ones, leading to a ‘superior’ human race. This theory was soon vilified, when the practices progressed into egregious human rights abuses. Though this may seem like a dystopian fantasy, the conversation around eugenics is resurfacing again when considering the potential risks of gene editing tools like CRISPR-Cas9. Accompanying the exciting possibilities of genetic advancements is the looming risk of eradicating variation through the pursuit for perfection. The surreal concept of designer babies has the potential to significantly alter the course of human evolution by allowing parents to select embryos created through IVF that, for example, do not carry the gene for cystic fibrosis. However, the capabilities of gene editing may not necessarily be limited to disease resistance. By enabling the selection and enhancement of specific traits, such as intelligence, appearance and physical prowess, humanity could actively direct its own genetic future. This control could lead to a population with reduced genetic diversity, as certain traits are favoured over others. By completely eradicating the safety net that diversity provides, we may become more vulnerable to new diseases or drastic environmental changes. The acceleration of evolutionary changes that would naturally take millennia could create a scenario where human evolution is driven purely by technological intervention rather than natural selection. Perhaps the main flaw in this system is assuming superiority between different genes. Genes traditionally viewed as harmful can sometimes confer unexpected advantages, due to the interplay between genetics and environmental factors. For instance, the gene responsible for sickle-cell anaemia may provide an advantage for those living in malaria-endemic regions. Those carrying just one copy of the gene could be less susceptible to malaria, therefore giving them the survival advantage. How can we decide if a gene is beneficial or destructive? Clearly, this can only be determined by numerous factors, with context being crucial in interpreting a gene’s advantages. This duality highlights the necessity of a broader understanding on the impacts of genetic diversity before advancing genetic treatments. Inevitably, we will soon have the potential to move beyond natural selection. But will that truly eradicate evolution? Despite the pace at which gene editing with CRISPR-Cas9 is developing, long-term patterns of evolution remain unpredictable due to external phenomena. Until we can successfully predict cataclysmic meteor strikes or climate cycles, our evolution will still, at least partly, be governed by chance.