Identification of genes and gene pathways affecting fertility in male Drosophila

Abstract

Drosophila females remate generating an opportunity for sperm competition. Normally the second male to mate sires the majority of progeny; however, conspecific sperm precedence is the phenomena whereby the male of the same species as the female fathers the majority of the progeny regardless of mating order. I surveyed D. simulans laboratory strains carrying D. mauritiana P-element insertions (IG lines) for their ability to sire progeny when second to mate. I found significant variation in the proportion of progeny sired by IG lines, with lines showing sperm competitive breakdown (P2< 0.5). I identified two loci that account for conspecific sperm precedence between D. simulans and D. mauritiana. 81 candidate genes were identified and narrowed down the list on the basis of differences in male reproductive tract gene expression to five (P< 0.05) or eight (P<0.1) genes. A larger concentration of differentially regulated genes within the 89B position was found. Using coding sequence data I identified 10 genes as candidate conspecific male precedence genes. Genes in the 89B region come to light as candidates for future functional studies of conspecific male precedence.