PgmNr P2120: Post-mating transcriptome profiles of Drosophila novamexicana females after con- and heterospecific copulation.

Authors:
Y. Ahmed; A. Clark


Institutes
Cornell University, Ithaca, NY.


Abstract:

Post-copulatory sexual selection is a potent evolutionary force that can cause rapid divergence of reproductive proteins between closely related species. In many animal taxa, including Drosophila, several species are reproductively isolated exclusivley by strong gametic incompatibilities, which result in reduced fertilization in heterospecific copulations. One such species pair are the closely related D. americana and D. novamexicana, two members of the virilis group that show strong gametic incompatibilitiy when crossed in the lab, especially when D. americana males mate with D. novamexicana females (~1% fertilization). We are actively expoliting this system to better understand the genetic and molecular basis of post-copulatory sexual selection, in particular the role female proteins play in male-female gametic interactions. Here we examine mating-induced transcriptome changes in D. novamexicana females after mating. In particular, we compare the regulatory response across three tissues (lower reproductive tranct, ovaires, and head) and between conspecific and heterospecific inseminations at several time-points post-insemination. The majority of transcripts that are affected by mating are shared between conspecific and heterospecific matings, but a subset are either uniquely responsive in either the conspecific or the heterospecific cross. We find that several Gene Ontology (GO) terms are enriched among mating-responsive genes, including proteolysis, immune response and proteasome degradation. We also find that several male-specific genes (both from the accessory glands and testes) show increases in abundance in the female reproductive tract after mating. These preliminary results suggest that mating and/or copulation trigger a coordinated regulatory response that can be disrupted when copulation occurs between species, and that the transfer of male RNAs during mating might have a functional consequence.