Manipulating sex determination pathways for pest control

CRISPR/Cas9-based gene drives can introduce and spread genes and desirable traits into wild populations, offering a wide range of potential uses in insect pest control. For example, they can spread sterility and reduce agricultural pest populations in a targeted and environmentally friendly way. Gene drive technologies have often targeted highly basal elements of the sex determination pyramid to reduce the fitness of, or kill, females. More efficient and controllable technologies can be designed to manipulate higher-level regulators of sexual fate to effect complete sex conversion (female to male). These can potentially be deployed across a broad range of gene drive systems, to spread through a target population, causing a growing wave of sex ratio distortion, leading to rapid pest population reduction.
This project will develop novel gene drives that utilise sex conversion as a population control measure by converting crop-damaging females into benign males. The model is a global agricultural pest, the medfly (Ceratitis capitata). The project aims to manipulate sex determination pathways in the medfly to effect population control through gene editing, a gene drive system in which males are converted into XX pseudomales. The designs produced will then be evaluated in tests and theory.