Vomeronasal receptor families in the deer mouse Peromyscus maniculatus: Towards an evolutionary analysis

Chemoreceptors are the first element in a complex pathway that can ultimately affect behavior -- changes in their biochemical properties or expression pattern have the potential to modulate specific behavioral responses. In particular, the activation of sensory neurons in the VNO is directly associated with changes in behavior, such as aggression, avoidance or mating. To understand the diversity and evolution of pheromone systems in wild populations, we are studying deer mice (genus Peromyscus), which diverged from Mus approximately 25 MYA. Here, we report on the characterization of VNO receptors from the most common and widespread species in North America, P. maniculatus. In total, we identified 150 and 90 putative V1R and V2R genes, respectively, in the Peromyscus genome, fewer than in M. musculus (239 and 120, respectively). While clades previously identified in Mus have representatives in Peromyscus, our phylogenetic reconstructions indicate that most gene duplications took place after the split between the two lineages; several clades show sign of lineage-specific expansion or contraction. These differences in the chemosensory receptor repertoires likely reflect the difference in habitats as well as social and mating behavior of deer mice. The establishment of a functional map of receptor-ligand interactions will be discussed.