Comparative transcriptomics of male reproductive tissue in Peromyscus

Sperm competition has shaped an extraordinary array of rapidly evolving reproductive traits, many of which are integrative parts of the speciation process. Despite the tremendous impact sexual selection potentially has on natural diversity, very few studies have established direct links between the genetic causes and the fitness consequences of reproductive traits, particularly in vertebrates. This study focuses on male reproductive traits that differ greatly between two sister species of deer mice (Rodentia: Cricetidae: Peromyscus) as a consequence of highly divergent mating strategies, and hence different levels of sperm competition. The oldfield mouse Peromyscus polionotus subgriseus is a monogamous species lacking sperm competition. In contrast, the prairie deer mouse Peromyscus maniculatus bairdii is a highly promiscuous species, and sperm competition is likely to be fierce. We examine the reproductive transcriptome of these two species in order to elucidate the genetic basis of variation in male reproductive physiology.