UC San Diego

Malaria is among the world's deadliest diseases, killing over half a million people annually. Suppressing the principal vector, the mosquito Anopheles gambiae, is among the most effective malaria control strategies. Here, we expand the vector control toolkit in A. gambiae by developing two controllable and scalable vector suppression technologies in the species: Ifegenia and pgSIT. To develop Ifegenia, we characterize a candidate female essential gene, femaleless (fle), and show that mosaic fle knockout causes complete female death but leaves males apparently healthy. We demonstrate that these Δfle males can pass down Cas9, gRNA and Δfle alleles at Mendelian rates and eliminate females for multiple generations. Through modeling, we demonstrate that releasing Δfle males has potential to confinably suppress wild populations. Additionally, we adapt the population suppression technology pgSIT to A. gambiae. SIT involves releasing sterile male mosquitoes into the wild to mate with wild females, sterilizing the females and causing single-generation population suppression. In pgSIT, sterile males are produced by crossing together separate Cas9- and gRNA- expressing lines to knock out male fertility genes and female essential genes- and produce sterile males- in the F1 generation. Here, we develop a pgSIT system in A. gambiae that almost completely eliminates females and sterilizes males. We demonstrate that these sterile males have good longevity and are able to suppress a population in cage trials. Together, we develop two controllable technologies that are critical new additions to the anti-malarial vector control toolkit.