Pleiotropic Chemoreceptors Facilitate The Maintenance Of Signal-Receptor Coupling In Pheromonal Communication

Diversity in pheromonal systems plays an essential role in maintaining mating boundaries between closely related species. To preserve fitness, it has been hypothesized that pheromone-receptor coupling is maintained via strong purifying selection. However, because strong negative selection antagonizes diversity, how pheromonal systems retain potential for plasticity is puzzling. Here we propose that receptor pleiotropy could represent one possible mechanism for retaining the capacity of pheromone-receptor pairs to diversify. Specifically, we demonstrate that Gr8a, a member of the gustatory receptor family in Drosophila, is a pleiotropic gene that contributes to both the perception and production of specific mating signals in the peripheral nervous system and pheromone producing oenocytes, respectively. Together, our data provide an elegant genetic solution to a long-standing evolutionary conundrum.