Roles of female and male genotype in post-mating responses in Drosophila melanogaster

Purpose: Mating induces a multitude of changes in female behavior, physiology and gene expression. Interactions between female and male genotype lead to variation in post-mating phenotypes and reproductive success. So far, few female molecules responsible for these interactions have been identified. Methods: We used Drosophila melanogaster from five geographically dispersed populations to investigate such female x male genotypic interactions at the female transcriptomic and phenotypic levels. Methods: Females from each line were singly-mated to males from the same five lines, for a total of 25 combinations. To assess whether female x male genotypic interactions affect the female post-mating transcriptome, next-generation RNA sequencing was performed on virgin and mated females at 5 to 6 hours post-mating. Results: Seventy-seven genes showed strong variation in mating-induced expression changes in a female x male genotype-dependent manner. These genes were enriched for immune response and odorant-binding functions, and for expression exclusively in the head. Conclusions: The transcriptional variation found in specific functional classes of genes might be a read-out of female x male compatibility at a molecular level. Understanding the roles these genes play in the female post-mating response will be crucial to better understand the evolution of post-mating responses and related conflicts between the sexes. Overall design: Five Drosophila melanogaster inbred lines were used. These lines are derived from five geographically dispersed populations (Global Diversity Lines Beijing 04; Ithaca 16; Netherlands 01; Tasmania 01 and Zimbabwe 184 – the latter line was collected in Africa, but turned out to be a recent migrant) (Grenier et al., 2015). Virgin females from each line were singly-mated to virgin males from each of the five inbred lines, similar to a 5x5 full factorial design. For RNAseq, mated females were flash frozen 5 to 6h after the start of mating. Age-matched virgin females were flash-frozen in parallel. Three independent biological replicates were generated for each of the 25 mating combinations and for virgin females of each genotype (90 samples total). Flies from each replicate were collected from separate bottles, and matings for all three replicates were set up simultaneously. RNA was extracted from five to ten pooled females per replicate.

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Delbare SYN, Chow CY, Wolfner MF, Clark AG