Genetic approaches to the development of novel designs for population control of two vector mosquitoes: Aedes aegypti and Culex quinquefasciatus.

Thesis

The prevention or reduction of infectious pathogen transmission is essential for safeguarding human health and species conservation, and can be achieved through vector control. New genetics-based innovations have proven to be a viable solution for the successful suppression or eradication of insect vectors, whilst also providing opportunities for further improvements and enhancements. In this thesis, I examine a vector control approach incorporating genetically engineered late-acting lethality, and investigate the character and function of the genetic elements that could lead to improvement of this approach. I start by assessing the functionality of the late-acting, doxycycline-repressible lethal system in transgenic Aedes aegypti. I find that the induced lethality is specific to the late developmental stage and occurs in the vast majority of the individuals carrying the lethal transgene. I also show that the induced phenotype is strongly repressible in the presence of the antidote, which is a crucial prerequisite of a practical RIDL (Release of Insect carrying Dominant Lethal gene) system. Next, I investigate the Culex quinquefasciatus Actin-4 gene and its potential use to induce a flightless phenotype. I find that the expression of the Actin-4 is sex-specific and, by generating a novel mutant via gene editing, that the gene is haploinsufficient or dominant negative in inducing the flightless phenotype in females. Additionally, I provide further support for the effectiveness of the recently discovered CRISPR/Cas9 system by showing that it successfully induces targeted editing of the Actin-4 gene. My findings provide novel genetic tools for the development of various genetics-based strategies for control of invasive vector mosquitoes.

Authors: Flis, I

• Alternative title: Genetically engineered late-acting lethality as a strategy for control of invasive vector mosquitoes.
• Type of award: MSc by Research
• Level of award: Masters
• Awarding institution: University of Oxford
• Language: English
• Keywords: CRISPR/Cas9; Engineered lethality; Aedes aegypti; Culex quinquefasciatus; Gene editing; Actin-4 gene; Vector control; Transgenic mosquito(es)
• Subjects: Mosquito control; Genetic engineering