The government of New Zealand may soon deploy a futuristic tool to solve an old problem, unique to their biosphere. That problem is the invasive species — like rabbits, rats, and stoats — that have wreaked havoc on native species that have not evolved to
ideal with predation. Previous attempts to gain control of these invaders have been unwieldy (like traps), and have sometimes backfired in allowing new invasive species to gain a foothold in the country (like the above-named stoats, imported in the 1880s to deal with all the danged rabbits). But New Zealand has pledged to go “predator free” by 2050, and is considering adding to their quiver everyone’s favourite gene editing tool, CRISPR.
While very much in the experimental stages, the idea goes something like this: scientists can use CRISPR to cut out and readjust portions of a target animal’s DNA; to, for example, prevent them from having female offspring. Using a “gene drive” to push this artificial change through to successive generations means that his glitch becomes essentially inheritable, and the population of rabbits or rats or stoats naturally crashes within a few iterations.
While real world gene adjustments have been accomplished only with yeast and fruit flies, scientists are confident the technique can scale up. If applied to New Zealand’s invasive species problem, it would eliminate the need for costly trapping programs, and for poisons that could go where they shouldn’t.
An interesting hiccup involves keeping the edit going through enough generations that it manages to reach its goal. Evolution is powerful, and quick enough that it could “write” a workaround for exactly what the edited gene is prevented from doing. But:
“[R]esearchers propose a way to redesign gene drives in order to work around that immunity, hypothesizing that a more complex architecture would make it difficult for a mutation to occur in a short period of time. Instead of just including instructions for a gene drive to cut a piece of DNA in one place, their architecture it cuts in multiple places, meaning it would require multiple mutations to overwrite the drive. They also suggest targeting genes less likely to mutate in the first place, because they are essential to a species’ fitness.”
If scientists can surmount this obstacle, they could be well on their way to establishing the most minimally… um, invasive, way of dealing with invasive species that we’ve seen. I’ve always believed that we should take our impact on this planet seriously, and attempt to undo what damage we can. But, if we learn something really cool about the mechanics of genes on the way, all the better!