Polyandry and sex-specific gene expression

Abstract

Polyandry is widespread in nature, and has important evolutionary consequences for the evolution of sexual dimorphism and sexual conflict. Although many of the phenotypic consequences of polyandry have been elucidated, our understanding of the impacts of polyandry and mating systems on the genome is in its infancy. Polyandry can intensify selection on sexual characters and generate more intense sexual conflict. This has consequences for sequence evolution, but also for sex-biased gene expression, which acts as a link between mating systems, sex-specific selection and the evolution of sexual dimorphism. We discuss this and the remarkable confluence of sexual-conflict theory and patterns of gene expression, while also making predictions about transcription patterns, mating systems and sexual conflict. Gene expression is a key link in the genotype–phenotype chain, and although in its early stages, understanding the sexual selection–transcription relationship will provide significant insights into this critical association.

The polyandry revolution

“…The sex-specific patterns of sexual selection caused by polyandry and the sex-specific role of such genes suggest that their expression should be strongly sexually dimorphic, and that when expressed in both sexes, their expression should be sexually antagonistic: beneficial in one sex but deleterious in the other, owing to divergent phenotypic optima of males and females, an evolutionary constraint known as 'intra-locus conflict' [24]. In their review, Mank et al [25] explore the ways in which male and female transcriptomics and gene expression patterns are influenced by sexual conflict and sexual selection in polyandrous mating systems. There is evidence that selection generated by female multiple mating has had a major impact on the way genes are regulated and expressed [25].…”

“…In their review, Mank et al [25] explore the ways in which male and female transcriptomics and gene expression patterns are influenced by sexual conflict and sexual selection in polyandrous mating systems. There is evidence that selection generated by female multiple mating has had a major impact on the way genes are regulated and expressed [25]. This is particularly apparent for genes with sexually antagonistic effect.…”

Polyandry and postcopulatory sexual selection in a wild population

“…; Mank et al . ; Wedell ), the maintenance of genetic variation (Chesser & Baker ; Zeh et al . ; Holman & Kokko ) and the nature of sexual conflict (Parker & Birkhead ).…”

Proximate perspectives on the evolution of female aggression: good for the gander, good for the goose?

“…Gene regulation (transcription) can be influenced by experience or by organizational effects of hormones, so differential gene expression is important in the context of sexual conflict because it allows potentially adaptive trait modification over the backdrop of the same genome [91,92]. Indeed, sex differences in gene expression are a common solution to sexual conflict [21,93], one that is mediated by sex steroids to some degree [94]. Genes with sexually dimorphic expression also tend to evolve more rapidly that those without sex biases [95,96], and this accelerated evolution supports an important stipulation of sex-specific mechanisms of behaviour because it permits molecular mechanisms to diverge (adaptively) between the two sexes.…”