Scientists debate pros, cons of editing genes to stop virus-carrying mosquitos

December 07, 2017

We’d all love to get rid of mosquitos, it’s true. But as sweets, junk food and binge-watching TV all night have prompted us to ask: Are the things we want always the best for us?

That brings us to gene drives — or at least, certain applications of them. Gene drives are scientifically-modified genes that spread desirable genetic traits in living things. Much discussion around gene drives centers on mosquitos: Can we use gene drives to make mosquitos less troublesome for humans? The topic is controversial.

It’s not just a matter of keeping ourselves from being annoyed by the buzzy little bloodsuckers and the itchy bites they leave behind. Malaria, an illness spread widely by mosquitos, kills nearly half a million people each year. Other sicknesses, like Zika, dengue and yellow fever, are carried by the bugs. If we can change the way mosquitos infect people, countless lives could be saved.

Research into gene drives has suggested some ideas for affecting mosquitos in ways that could reduce their ability to spread diseases like malaria. If mosquitos could be edited in such a way to make it harder for them to carry viruses and parasites, as some researchers are investigating, sicknesses would spread less rapidly. Other ideas have been proposed to make mosquitos infertile, or to make all future offspring a single sex, preventing reproduction.

Other uses for gene drives have been proposed. They could be used to eliminate invasive species that only bring harm to their new ecosystems, or could be used to save nearly-extinct species.

But some experts warn that modifying the genome of any species too dramatically could bring unintended, irreversible consequences that may affect our ecosystems in ways we might not expect. A change in one species behavior or population may affect another’s. Genetic modifications might result in further off-target mutations. Some of these aftershocks could be irreparably damaging, these experts fear. They also worry the technology could be used to hurt other humans.

Others argue that to save human lives, we have no other option, as many dangerous illnesses don’t have effective vaccines and many disease-ridden countries lack the public health infrastructure to tackle the problem.

Evolutionary theorist Austin Burt, who heads a gene drive project called Target Malaria, published a paper that sums up the dilemma faced by researchers. As Technology Review reports, his paper concludes, “Clearly, the technology described here is not to be used lightly. Given the suffering caused by some species, neither is it obviously one to be ignored.”

Category: Genomics