In recent years, synthetic Cas9-based homing endonuclease gene (HEG) systems have garnered substantial interest as a groundbreaking genetic biocontrol method. The nuclease (Cas9+single guideRNA) and the ‘cargo’ (genetic trait) allow inheritance biasing (homing), meaning desired traits can propagate within wild populations over time. However, optimisation of nuclease activity in specific spatiotemporal contexts stands in the way of establishing viable Cas9-HEG systems. This challenge stems mainly from an incomplete understanding of the precise cellular stages optimal for homing. To unravel this complexity, the student will refine the hybridisation chain reaction (HCR) technique for fluorescence in situ hybridisation (FISH) and immunofluorescence (IF) to visualise essential genetic components—sgRNA, Cas9 mRNA, and Cas9 protein—within insect strains (mosquitos, Aedes aegypti). Successful candidates will receive comprehensive training to execute a series of experiments during their summer project, including mosquito husbandry and tissue preparation, HCR-FISH and HCR-IF, and data analysis. This should develop a robust framework not only applicable to Aedes aegypti but also adaptable to other species recalcitrant to HEG approaches. Achieving this objective will offer significant implications for genetic biocontrol initiatives targeting diverse pest species.  Students will be expected to present their findings orally at a research day in York in September 2024.