help button home button Genetics Science
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Genetics, Vol. 177, 1395-1416, November 2007, Copyright © 2007
doi:10.1534/genetics.107.078683

This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Data Supplement
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by McBride, C. S.
Right arrow Articles by O'Meara, B. C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by McBride, C. S.
Right arrow Articles by O'Meara, B. C.

Five Drosophila Genomes Reveal Nonneutral Evolution and the Signature of Host Specialization in the Chemoreceptor Superfamily

Carolyn S. McBride*,1 and J. Roman Arguello{dagger},1,2

* Center for Population Biology, University of California, Davis, California 95616 and {dagger} Committee on Evolutionary Biology, University of Chicago, Chicago, Illinois 60637

2 Corresponding author: Department of Ecology and Evolution, 1101 E. 57th St., Chicago, IL 60637. E-mail: arguello{at}uchicago.edu

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 Ka/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.

 

APPENDIX: Estimating Different Rates of Gene Loss on a Tree

Brian C. O'Meara

Center for Population Biology, University of California, Davis, California 95616


This article has been cited by other articles:


Home page
 GeneticsHome page
M. Ashburner
Drosophila Genomes by the Baker's Dozen
Genetics, November 1, 2007; 177(3): 1263 - 1268.
[Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2007 by the Genetics Society of America.