The use of gene drives – or any genetic pest management method – involves releasing gene drive-carrying organisms, e.g. mosquitoes, to mate with wild mosquitoes in the target area. Their offspring carry the gene drive which then goes off to do whatever it was designed to do. But what about all the other (non-gene-drive) genes in the released mosquitoes? What happens to them? They also enter the population’s gene pool, though unlike the gene drive they have no special mechanism to allow them to spread. Does that matter? Contrary to some recent speculation, probably not, at least in most cases.

Genetic control of mosquitoes involves introducing some sort of modified heritable trait into a wild mosquito population. That involves rearing modified mosquitoes in the lab and releasing them to mate with the target wild mosquito population. That mating delivers the modified genetic trait into the wild population and, if that’s a gene drive and the conditions are right, that gene drive will start to do its thing in that population, for example start to increase in frequency.