Gene drive that results in addiction to a temperature-sensitive version of an essential gene triggers population collapse in .

One strategy for population suppression seeks to use gene drive to spread genes that confer conditional lethality or sterility, providing a way of combining population modification with suppression. Stimuli of potential interest could be introduced by humans, such as an otherwise benign virus or chemical, or occur naturally on a seasonal basis, such as a change in temperature. () selfish genetic elements use Cas9 and guide RNAs (gRNAs) to disrupt endogenous versions of an essential gene while also including a version of the essential gene resistant to disruption. spreads by creating loss-of-function alleles of the essential gene that select against those lacking it, resulting in populations in which the provides the only source of essential gene function. As a consequence, if function of the , a kind of Trojan horse now omnipresent in a population, is condition dependent, so too will be the survival of that population. To test this idea, we created a in in which activity of an essential gene, , requires splicing of a temperature-sensitive intein (TS- ). This element spreads to transgene fixation at 23 °C, but when populations now dependent on Ts- are shifted to 29 °C, death and sterility result in a rapid population crash. These results show that conditional population elimination can be achieved. A similar logic, in which activity is conditional, could also be used in homing-based drive and to bring about suppression and/or killing of specific individuals in response to other stimuli.