The evolutionary ecology of viruses and antiviral RNAi in insects

All organisms suffer from viral infections and have consequently evolved some form of antiviral immunity. The human ‘adaptive’ immune system only exists in jawed vertebrates and their closest relatives, and instead almost all other eukaryotes—including plants, fungi, and most animals—have an antiviral defence mechanism based on RNA interference. Since RNAi was discovered in the mid-1990’s it has won a Nobel Prize for its discoverers (Craig Mello and Andrew Fire in 2006) and has revolutionised our understanding of many fundamental cellular processes. However, although we’ve learned much about the mechanistic basis of antiviral RNAi, we still have a great deal to learn about the selective pressures that have driven its evolution.
Our lab studies the evolution and ecology of antiviral immune responses, using the RNAi response of Drosophila as a model to understand the evolution of insect-virus interaction and immunity more generally. This includes work on the phylogenetic origins of antiviral RNAi and the evolution of RNAi-pathway genes, the evolutionary ecology of Drosophila viruses in the wild, and evolution in response to ‘endogenous retroviruses’ and transposable elements.
Our work makes use of both experimental (viral infections, next-generation sequencing) and population-genetic approaches to understand how host-parasite interaction drives the co-evolution of both host and virus genes. Recently, we have shown that RNAi genes in Drosophila have particularly high rates of adaptive evolution[1], we have identified a number of new viruses in Drosophila[2], and we have shown how host phylogeny can account for variation in viral susceptibility[3]. Our on-going work focuses on the evolution and ecology of natural viral pathogens of Drosophila, and on the diversification of antiviral RNAi between taxa.
This project will focus on the evolutionary ecology of Drosophila viruses in the wild. It will likely include sequence analysis to understand their prevalence, distribution, and population genetics (‘phylodynamics’), combined with experimental work to place the evolutionary genetics in a functional context (fitness consequences, transmission, host-specialisation). However, the project can easily be tailored to suit the applicant’s strengths and interests. If you would like more detail on what this project might involve, or what other research areas are available within the lab, please email [Email Address Removed].