Until this obstacle is overcome, the technology is unlikely to succeed in the wild.
“These things are not going to get too far in terms of eradicating a population,” says Michael Wade, an evolutionary geneticist at Indiana University Bloomington. Gene drives could result in the genetic isolation — in which populations do not mate with each other — of groups that manage to avoid inheriting the modified genetic code, he and his colleagues found. And gene variants that decrease a population’s propensity to mingle with other populations — such as those that limit flight capacity in insects — would suddenly prove beneficial and could spread.
Resistance to gene drives is unavoidable, so researchers are hoping that they can blunt the effects long enough to spread a desired mutation throughout a population. Some have floated the idea of creating gene drives that target multiple genes, or several sites within the same gene, diminishing the speed with which resistance would develop. By surveying a species’ natural genetic diversity, researchers could target genes common to all individuals.