Identifying the genetic targets of sexual selection

Sexual selection influences genomic divergence, for example genes which show sex-biased gene expression are often the most divergent between species. This is sometimes more pronounced in sexually dimorphic species and is therefore thought to reflect the strength of sexual selection. Currently different (even contrasting) patterns of genomic divergence can be interpreted as supporting an influence of sexual selection and conflict on genomic divergence. The resolution and reliability of such patterns is highly debated and unclear. Identifying the precise targets of sexual selection and the signature this leaves in the genome is critical to understanding the importance of this form of selection in evolutionary divergence and speciation. The proposed work will provide an exceptional contribution to resolving how sexual selection acts on genotypes, by leveraging an experimental evolution study which has identified several candidate genes. We will complete functional genetic analyses to confirm the role of these genes and measure the fitness consequences of gene knock outs. We will then upscale this to natural populations and assess the performance of genomic signatures of divergence in natural populations from a range of ecological contexts and levels of evolutionary divergence. This work will provide unprecedented insight into the role of sexual selection in genomic divergence.

One of the emerging issues in contemporary biology is understanding what inferences can be drawn reliably from extensive sequencing data. Understanding adaptation to environmental conditions and biological processes such as sexual selection relies on accurately inferring genomic differences that have evolved under such selection rather than drift or demographic factors. We will use two approaches to inferring the action of sexual selection on genomic divergence. Firstly we will experimentally generate novel knock out mutants for candidate genes in a species with few such resources. Secondly we will complete novel sequencing data for laboratory populations where we have manipulated the source of selection, then assess the behaviour of population genetic measures derived from these lines in natural populations undergoing evolutionary divergence. These data are extremely timely for answering fundamental topical questions about the inference of evolutionary processes from large scale genomic data, vital for understanding genetic divergence in all organisms. They will also be used to contribute to our outreach activities including introducing genomics and bioinformatics into the school curriculum.