The origins of novel protein interactions during animal opsin evolution.
BACKGROUND
Biologists are gaining an increased understanding of the genetic bases of phenotypic change during evolution. Nevertheless, the origins of phenotypes mediated by novel protein-protein interactions remain largely undocumented.


RESULTS
Here we analyze the evolution of opsin visual pigment proteins from the genomes of early branching animals, including a new class of opsins from Cnidaria. We combine these data with existing knowledge of the molecular basis of opsin function in a rigorous phylogenetic framework. We identify adaptive amino acid substitutions in duplicated opsin genes that correlate with a diversification of physiological pathways mediated by different protein-protein interactions.


CONCLUSIONS
This study documents how gene duplication events early in the history of animals followed by adaptive structural mutations increased organismal complexity by adding novel protein-protein interactions that underlie different physiological pathways. These pathways are central to vision and other photo-reactive phenotypes in most extant animals. Similar evolutionary processes may have been at work in generating other metazoan sensory systems and other physiological processes mediated by signal transduction.
Plachetzki
David C
DC
Ecology, Evolution and Marine Biology, University of California at Santa Barbara, Santa Barbara, California, United States of America.
Degnan
Bernard M
BM
Oakley
Todd H
TH
D000818:Animals; D003063:Cnidaria / Q000378:metabolism; D019143:Evolution, Molecular; D017403:In Situ Hybridization; D008027:Light; D016013:Likelihood Functions; D008390:Markov Chains; D008954:Models, Biological; D010641:Phenotype; D010802:Phylogeny; D025941:Protein Interaction Mapping; D017299:Rod Opsins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction; D013045:Species Specificity
D017299:Rod Opsins