Five Drosophila genomes reveal nonneutral evolution and the signature of host specialization in the chemoreceptor superfamily

Carolyn S. McBride, J. Roman Arguello

Research output: Contribution to journalArticlepeer-review

159 Scopus citations


The insect chemoreceptor superfamily comprises the olfactory receptor (Or) and gustatory receptor (Gr) multigene families. These families give insects the ability to smell and taste chemicals in the environment and are thus rich resources for linking molecular evolutionary and ecological processes. Although dramatic differences in family size among distant species and high divergence among paralogs have led to the belief that the two families evolve rapidly, a lack of evolutionary data over short time scales has frustrated efforts to identify the major forces shaping this evolution. Here, we investigate patterns of gene loss/gain, divergence, and polymorphism in the entire repertoire of ∼130 chemoreceptor genes from five closely related species of Drosophila that share a common ancestor within the past 12 million years. We demonstrate that the overall evolution of the Or and Gr families is nonneutral. We also show that selection regimes differ both between the two families as wholes and within each family among groups of genes with varying functions, patterns of expression, and phylogenetic histories. Finally, we find that the independent evolution of host specialization in Drosophila sechellia and D. erecta is associated with a fivefold acceleration of gene loss and increased rates of amino acid evolution at receptors that remain intact. Gene loss appears to primarily affect Grs that respond to bitter compounds while elevated K a/Ks is most pronounced in the subset of Ors that are expressed in larvae. Our results provide strong evidence that the observed phenomena result from the invasion of a novel ecological niche and present a unique synthesis of molecular evolutionary analyses with ecological data.

Original languageEnglish (US)
Pages (from-to)1395-1416
Number of pages22
Issue number3
StatePublished - Nov 2007
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Genetics


Dive into the research topics of 'Five Drosophila genomes reveal nonneutral evolution and the signature of host specialization in the chemoreceptor superfamily'. Together they form a unique fingerprint.

Cite this