Rapid Divergence Of The Copulation Proteins In The Drosophila Dunni Group Is Associated With Hybrid Post-Mating-Prezygotic Incompatibilities

Background: Proteins involved in post-copulatory interactions between males and females are among the fastest evolving genes in many species and this has been attributed to reproductive conflict. Likely as a result, these proteins are frequently involved in cases of post-mating-prezygotic isolation between species. The Drosophila dunni subgroup consists of a dozen recently diverged species found across the Caribbean islands with varying levels of hybrid incompatibility. Results: : We performed experimental crosses between species in the dunni group and find evidence of hybrid inviability likely due to post-mating-prezygotic incompatibilities. We next assessed rates of evolution between these species genomes and find evidence of rapid evolution and divergence of some reproductive proteins, specifically the seminal fluid proteins. Conclusions: : This work suggests the rapid evolution of seminal fluid proteins can lead to post-mating-prezygotic isolation, which acts as a barrier for gene flow between even the most closely related species.