“Gene drive offers a way of altering, reducing, or even eliminating these deadly mosquitoes in the wild by ensuring that genomic changes are preferentially inherited by offspring,” Esvelt told Gizmodo. “CRISPR gene drives capable of affecting the worst offenders are nearly within our reach.”


On average, genes have about a 50 percent chance of being inherited, but some preferential genes can be altered to have a heightened chance of being passed on. These genes can still proliferate in a population even if they reduce a species’ overall reproductive potential. Scientists would like to genetically modify animals in the wild by adding, removing, or introducing entirely new traits and capacities. Obviously, scientists can’t go out and physically modify each and every animal, but they can “drive” a gene through the population using a select number of transgenic organisms created in the lab.

The beauty of this technique is that modifications are spread by the mosquitoes themselves. Researchers have already figured out a way to create mosquitoes that produce an overabundance of males, which works to reduce their numbers. Other traits, like an immunity to Zika and dengue, could likewise be “driven” into wild populations of mosquitoes. Over time, the human-designed mosquitoes should replace the original ones.

Image for article titled It's Time to Declare War on Mosquitoes

How modified genes can be driven through a population. “By ensuring that the gene is almost always inherited, the gene drive can spread the altered gene through a population over many generations, even if the associated trait reduces the reproductive fitness of each organism,” write the authors in Science. Via Kenneth A. Oye et al., 2014, Science.


Gene drives are nearly ready to be launched in areas where mosquitoes are most problematic. In anticipation, the WHO Special Programme for Research and Training in Tropical Diseases has issued guidelines for evaluating GMO mosquitoes, while the European Safety Food Authority has compiled a six-step protocol for assessing the environmental impacts of modified organisms. But regulatory gaps persist, leading Harvard geneticist George Church, MIT social scientist Kenneth Oye, and other US researchers to demand increased oversight. Writing in Science in 2014, the researchers called for stricter regulations in containment, testing, controlled release, and monitoring of gene drives.

“Given the rate at which gene drive technology is advancing now that we have CRISPR, we need to perform these safety studies as soon as possible, and engage in public discussions of whether, when, and how to intervene even sooner,” said Esvelt. “What level of support is needed? What if one country strongly supports engineering mosquitoes to save their children, but their neighbours don’t want to risk using a gene drive? How do you reconcile that fundamental conflict?”


In an email conversation with Gizmodo, Church added that a great deal is known about the biology and ecology of Aedes mosquitoes and that other non-gene-drive techniques, such those being deployed by Oxitec, are already protecting us from viruses. “We need broad societal brainstorming,” he wrote, “and critical consideration of potential risks, benefits, resistance, and timing of the various options.”

There’s no magic bullet. Rather, experts agree that a multifaceted approach is the best option, while making sure we don’t compromise our environment and health in the process.


“We need early discussion, transparent research, careful safeguards, community guidance, and a ample helping of humility if we’re going to build a responsive model of science capable of handling gene drives and other ecological interventions,” Esvalt said. “The bottom line is that we must balance the moral imperative of reducing human suffering against the unknowns, and do so together.”

Top image: Jim Cooke. Wolbachia image via Michigan State University.

Email the author at george@gizmodo.com and follow him @dvorsky.