The limits of sexual dimorphism: studying sexually antagonistic genetic variation in fruit flies

Males and females of the same species often differ in their morphology, physiology and behaviour, reflecting the sexes’ reproductive roles. But while sexual dimorphism is ubiquitous, recent work has highlighted that the divergence between the sexes is often incomplete and adaptive conflicts are ongoing between males and females. The conflicts arise from the fact that the sexes share a common genome, and the resulting genetic coupling between their traits can slow or even halt the evolution of sexual dimorphism. Populations can then accumulate ‘sexually antagonistic’ genetic polymorphisms, with variants that are beneficial to one sex but detrimental to the other, that can persist for long periods of time.

Sexual antagonism is a key contributor to the maintenance of fitness variation within populations and previous work has shown that genome-wide, antagonistic variation is present in many species. Nevertheless, we know little about the identity and function of the loci that harbour antagonistic variation, nor have we been able to infer the fitness effects of individual antagonistic alleles or the timescales over which they remain polymorphic. This PhD will contribute to ongoing work in my group to answer these questions. We do so with a combination of laboratory experiments (e.g. experimental evolution, genome editing) and computational population genetic analyses of lab-evolved and wild populations. Specific projects can be designed to suit your skills and interests.