Ilona Flis | bioRxiv Science

bioRxiv2016

Sex-biased gene expression in Drosophila melanogaster is constrained by ontogeny and genetic architecture

Sexual dimorphism is predicted to be constrained by the underlying genetic architecture shared between the sexes and through ontogeny, but whole-transcriptome data for both sexes across genotypes and developmental stages are lacking. Within a quantitative genetic framework, we sequenced RNA from Drosophila melanogaster at different developmental stages to examine sex-biased gene expression and how selection acts upon it. We found evidence that gene expression is constrained by both univariate and multivariate shared genetic variation between genes, sexes and developmental stages, but may be resolved by differential splicing. These results provide a comprehensive picture of how conflict over sexual dimorphism varies through development and clarifies the conditions under which it is predicted to evolve.

Genetics↗

bioRxiv2013

Genome-wide targets of selection: female response to experimental removal of sexual selection in Drosophila melanogaster

Despite the common assumption that promiscuity should in general be favored in males, but not in females, to date there is no consensus on the general impact of multiple mating on female fitness. Notably, very little is known about the genetic and physiological features underlying the female response to sexual selection pressures. By combining an experimental evolution approach with genomic techniques, we investigated the effects of single and multiple matings on female fecundity and gene expression. We experimentally manipulated the mating system in replicate populations of Drosophila melanogaster by removing sexual selection, with the aim of testing differences in short term post-mating effects of females evolved under different mating strategies. We show that monogamous females suffer decreased fecundity, a decrease that was partially recovered by experimentally reversing the selection pressure back to the ancestral promiscuous state. The post-mating gene expression profiles of monogamous females differ significantly from promiscuous females, involving 9% of the genes tested. These transcripts are active in several tissues, mainly ovaries, neural tissues and midgut, and are involved in metabolic processes, reproduction and signaling pathways. Our results demonstrate how the female post-mating response can evolve under different mating systems, and provide novel insights into the genes targeted by sexual selection in females, by identifying a list of candidate genes responsible for the decrease in female fecundity in the absence of promiscuity.

Evolutionary Biology↗