Comparative genomics uncovers unique gene turnover and evolutionary rates in a gene family involved in the detection of insect cuticular pheromones

MONTSERRAT TORRES-OLIVA; FRANCISCA CUNHA ALMEIDA; ALEJANDRO SÁNCHEZ-GRACIA; JULIO A. ROZAS

Genome Biology and Evolution

Oxford Journals

Año: 2016 vol. 8 p. 1734 - 1747

Chemoreception is an essential process for the survival and reproduction of animals.Many of the proteins responsible for recognising and transmitting chemical stimuli in insects are encoded by genes that are members of moderately sized multigene families. The members of the CheB family are specialized in gustatory-mediated detection of long-chain hydrocarbon pheromones in Drosophila melanogaster and play a central role in triggering andmodulating mating behavior in this species. Here,we present a comprehensive comparative genomic analysis of the CheB family across 12 species of the Drosophila genus.We have identified a total of 102 new CheB genes in the genomes of these species, including a functionally divergent member previously uncharacterized in D. melanogaster. We found that, despite its relatively small repertory size, the CheB family has undergone multiple gain and loss events and various episodes of diversifying selection during the divergence of the surveyed species. Present estimates of gene turnover and coding sequence substitution rates showthat this family is evolving faster than any knownDrosophila chemosensory family. To date, only other insect gustatory-related genes among these families had shown evolutionary dynamics close to those observed in CheBs. Our findings reveal the high adaptive potential of molecular componentsof the gustatory system ininsects and anticipate a key role of genes involved in this sensory modality in species adaptation and diversification.