View Program - 2022 Population, Evolutionary, and Quantitative Genetics Conference

Genetic conflict between the sexes – sexual antagonism – is predicted to occur in all species with distinct males and females. Sexual antagonism arises because males and females will often have different fitness optima for many phenotypes, but are hindered in evolving to these optima because they share the majority of their genome. A ‘tug-of-war’ results, in which genetic variants that are beneficial in one sex but detrimental in the other may be held at intermediate equilibrium frequencies, instead of spreading throughout the population or being eliminated. Sexual antagonism could thus be a powerful force maintaining genetic and phenotypic variation in a population, but we know little about how this form of selection acts on traits with complex genetic architectures.

Here, we investigate how sexually antagonistic selection acts on polygenic traits – traits encoded by many loci of varying effect size scattered throughout the genome. Using a combination of mathematical modelling and whole-genome simulations, we examine the scenario where a polygenic trait is under stabilizing selection for different fitness optima in males and females, and characterize the mutation-selection dynamics for this case. We characterize genetic correlations between the sexes across the allele frequency spectrum, and find that sexually antagonistic selection can generate the transient appearance of sex-specific control of a polygenic trait. Finally, we study how sexually antagonistic selection manifests in genomic regions with sex-biased transmission (such as sex chromosomes), and suggest new approaches to detecting sexually antagonistic selection in population genomic data.

The impact of sexually antagonistic selection on polygenic traits