Environmental plasticity in the intersexual correlation and sex bias of gene expression

Abstract

Intersexual genetic correlations are expected to constrain the evolution of sexual dimorphic traits, including the degree of sex-biased gene expression. Consistent with that expectation, studies in fruit flies and birds have reported that genes whose expression has a strong intersexual genetic correlation (\(r_{\mathrm{MF}}\)) show a lower level of sex-biased expression. However, it is known that both \(r_{\mathrm{MF}}\) and sex-biased expression can be affected by the environment. It is therefore unclear whether there is a consistent relationship between these 2 quantities across multiple environments.

In this paper, we study this relationship in the African malaria mosquito Anopheles gambiae. We show that both \(r_{\mathrm{MF}}\) and sex-biased expression change between environments. The change in sex-biased expression across environments is significantly correlated with dN/dS: greater changes in sex-biased expression are associated with higher values of dN/dS. Furthermore, the relationship between \(r_{\mathrm{MF}}\) and sex-biased expression is sensitive to the environment. We conclude that this relationship is sufficiently plastic that environmental effects should be considered in future studies.