Assessment of drive efficiency and resistance allele formation of a homing gene drive in the mosquito Aedes aegypti

Abstract

Aedes aegypti, known for transmitting viruses such as dengue, Zika and yellow fever, poses a significant public health threat. Conventional insecticides give rise to a range of issues, including ecological contamination and insect resistance. Hence, there is a pressing demand for environmentally-friendly, safer and more efficacious strategies for mosquito control. With the rapid advancement of the CRISPR/Cas9 system in gene function exploration and pest population control, substantial progress has been achieved in utilizing CRISPR/Cas9-based gene drive systems across various mosquito species. Only a few studies on gene drive technology have been conducted in Ae. aegypti. In this study, we constructed two complete drives for Ae. aegypti with different Cas9 promoters, each targeting kmo. Our drive based on PubCas9 had limited activity, but one with ExuCas9 exhibited super-Mendelian inheritance rates of approximately 60%. We observed low but detectable somatic activity of the drive and no evidence of maternally deposited Cas9. Germline resistance allele formation rates were similar to drive conversion rates, but most wild-type alleles in the germline remained uncut. Injections into the ExuCas9 drive line had 100% knockout efficiency among surviving offspring at three separate target genes. These results support the development and application of novel genetic pest control technologies aimed at combating Ae. aegypti.