Many strategies exist to manage invasive pests, ranging from poison to trapping, with varying degrees of success. Genetic technologies are increasingly being applied to insect pests, but not vertebrates. We propose to implement a genetic strategy to eradicate invasive mouse populations as another tool for pest control.
Mus musculus, the common house mouse, is one of the most widespread invasive species. Mice threaten human health, agriculture, and biodiversity on many islands, most specifically seabirds. The Farallon Islands are one example of a threat against biodiversity, with the ashy storm petrel being endangered by the predation of burrowing owls, which are attracted to the island due to the large population of invasive mice. Rodenticides are the most common method of eradicating mice, but their use leads to poisoning of non-target species and has limited efficacy against mice. An approach that could eliminate non-target species disruption would be to combine genetically engineered mice, which for example produce a daughterless phenotype, with a gene drive system that could make the genetic technique self-sustaining. There are naturally occurring and artificial gene drive systems. For this project, we have investigated exploiting a naturally occurring gene drive, the t-complex. Using the tw2 haplotype of the t-complex, which is a full t-haplotype lacking the embryonic recessive lethality found in many other t-complex alleles, we observed the tw2 haplotype being transmitted to offspring with a transmission distortion ratio of 92.4%. We are currently exploring combining this natural gene drive system with genetic alterations that would produce daughterless offspring as an approach to effectively crash an invasive population without adversely affecting other species.