Extensive local adaptation within the chemosensory system following Drosophila melanogaster's global expansion.
How organisms adapt to new environments is of fundamental biological interest, but poorly understood at the genetic level. Chemosensory systems provide attractive models to address this problem, because they lie between external environmental signals and internal physiological responses. To investigate how selection has shaped the well-characterized chemosensory system of Drosophila melanogaster, we have analysed genome-wide data from five diverse populations. By couching population genomic analyses of chemosensory protein families within parallel analyses of other large families, we demonstrate that chemosensory proteins are not outliers for adaptive divergence between species. However, chemosensory families often display the strongest genome-wide signals of recent selection within D. melanogaster. We show that recent adaptation has operated almost exclusively on standing variation, and that patterns of adaptive mutations predict diverse effects on protein function. Finally, we provide evidence that chemosensory proteins have experienced relaxed constraint, and argue that this has been important for their rapid adaptation over short timescales.
Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland.|Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA.
J Roman
JR
Arguello
Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland.|Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA.
Margarida
0000-0001-6639-3597
M
Cardoso-Moreira
Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA.
Jennifer K
JK
Grenier
Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA.
Srikanth
S
Gottipati
Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA.|Department of Biological Statistics and Computational Biology, Cornell University, Ithaca, New York 14853, USA.
Andrew G
AG
Clark
Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland.
Richard
R
Benton
D000222:Adaptation, Physiological; D000818:Animals; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics / Q000502:physiology*; D019143:Evolution, Molecular; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D017344:Genes, Insect; D005843:Geography; D005810:Multigene Family; D009154:Mutation / Q000235:genetics; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D012679:Sense Organs / Q000502:physiology*
D029721:Drosophila Proteins