Single-component CRISPR/Cas9-based gene drive in the yellow fever mosquito, Aedes aegypti

The yellow fever mosquito, Aedes aegypti, is a major vector of arboviruses including dengue, chikungunya, and Zika. Chemical insecticides are used to manage Ae. aegypti in urban areas, however this has led to insecticide resistance, resulting in the need to identify novel approaches to mitigate the burden of the arboviruses they vector. A novel approach to prevent arboviral transmission is to generate transgenic mosquitoes refractory to arbovirus infection. Such an approach requires a mechanism to spread and fix resistance genes through a population, for example, the use of CRISPR/Cas9-based gene drive systems. Gene drives copy themselves in the germline, resulting in super-Mendelian inheritance of the drive and any associated cargo. Recent work has established a split-drive system for Ae. aegypti, which is designed to be containable and non-persistent. Here we report on a single-component gene drive system in Ae. aegypti that is designed for persistent population replacement. For our work, we investigated the use of three promoters for Cas9 expression (nanos, β2-tubulin, zpg), as well as two genomic loci for targeting. We identified that both promoter selection and genomic target site strongly influenced the efficiency of the drive. We also observed that the formation of gene drive blocking indels differed greatly for the tested genomic loci. Overall, our drive system forms a platform for the further testing of driving anti-pathogen effector genes through Ae. aegypti populations.