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Rhodopsin Molecular Evolution in Mammals Inhabiting Low Light Environments

The ecological radiation of mammals to inhabit a variety of light environments is largely attributed to adaptive changes in their visual systems. Visual capabilities are conferred by anatomical features of the eyes as well as the combination and properties of their constituent light sensitive pigmen...

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Autores principales: Zhao, Huabin, Ru, Binghua, Teeling, Emma C., Faulkes, Christopher G., Zhang, Shuyi, Rossiter, Stephen J.
Formato: Texto
Lenguaje:English
Publicado: Public Library of Science 2009
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2790605/
https://www.ncbi.nlm.nih.gov/pubmed/20016835
http://dx.doi.org/10.1371/journal.pone.0008326
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author Zhao, Huabin
Ru, Binghua
Teeling, Emma C.
Faulkes, Christopher G.
Zhang, Shuyi
Rossiter, Stephen J.
author_facet Zhao, Huabin
Ru, Binghua
Teeling, Emma C.
Faulkes, Christopher G.
Zhang, Shuyi
Rossiter, Stephen J.
author_sort Zhao, Huabin
collection PubMed
description The ecological radiation of mammals to inhabit a variety of light environments is largely attributed to adaptive changes in their visual systems. Visual capabilities are conferred by anatomical features of the eyes as well as the combination and properties of their constituent light sensitive pigments. To test whether evolutionary switches to different niches characterized by dim-light conditions coincided with molecular adaptation of the rod pigment rhodopsin, we sequenced the rhodopsin gene in twenty-two mammals including several bats and subterranean mole-rats. We compared these to thirty-seven published mammal rhodopsin sequences, from species with divergent visual ecologies, including nocturnal, diurnal and aquatic groups. All taxa possessed an intact functional rhodopsin; however, phylogenetic tree reconstruction recovered a gene tree in which rodents were not monophyletic, and also in which echolocating bats formed a monophyletic group. These conflicts with the species tree appear to stem from accelerated evolution in these groups, both of which inhabit low light environments. Selection tests confirmed divergent selection pressures in the clades of subterranean rodents and bats, as well as in marine mammals that live in turbid conditions. We also found evidence of divergent selection pressures among groups of bats with different sensory modalities based on vision and echolocation. Sliding window analyses suggest most changes occur in transmembrane domains, particularly obvious within the pinnipeds; however, we found no obvious pattern between photopic niche and predicted spectral sensitivity based on known critical amino acids. This study indicates that the independent evolution of rhodopsin vision in ecologically specialised groups of mammals has involved molecular evolution at the sequence level, though such changes might not mediate spectral sensitivity directly.
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spelling pubmed-27906052009-12-17 Rhodopsin Molecular Evolution in Mammals Inhabiting Low Light Environments Zhao, Huabin Ru, Binghua Teeling, Emma C. Faulkes, Christopher G. Zhang, Shuyi Rossiter, Stephen J. PLoS One Research Article The ecological radiation of mammals to inhabit a variety of light environments is largely attributed to adaptive changes in their visual systems. Visual capabilities are conferred by anatomical features of the eyes as well as the combination and properties of their constituent light sensitive pigments. To test whether evolutionary switches to different niches characterized by dim-light conditions coincided with molecular adaptation of the rod pigment rhodopsin, we sequenced the rhodopsin gene in twenty-two mammals including several bats and subterranean mole-rats. We compared these to thirty-seven published mammal rhodopsin sequences, from species with divergent visual ecologies, including nocturnal, diurnal and aquatic groups. All taxa possessed an intact functional rhodopsin; however, phylogenetic tree reconstruction recovered a gene tree in which rodents were not monophyletic, and also in which echolocating bats formed a monophyletic group. These conflicts with the species tree appear to stem from accelerated evolution in these groups, both of which inhabit low light environments. Selection tests confirmed divergent selection pressures in the clades of subterranean rodents and bats, as well as in marine mammals that live in turbid conditions. We also found evidence of divergent selection pressures among groups of bats with different sensory modalities based on vision and echolocation. Sliding window analyses suggest most changes occur in transmembrane domains, particularly obvious within the pinnipeds; however, we found no obvious pattern between photopic niche and predicted spectral sensitivity based on known critical amino acids. This study indicates that the independent evolution of rhodopsin vision in ecologically specialised groups of mammals has involved molecular evolution at the sequence level, though such changes might not mediate spectral sensitivity directly. Public Library of Science 2009-12-16 /pmc/articles/PMC2790605/ /pubmed/20016835 http://dx.doi.org/10.1371/journal.pone.0008326 Text en Zhao et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Zhao, Huabin
Ru, Binghua
Teeling, Emma C.
Faulkes, Christopher G.
Zhang, Shuyi
Rossiter, Stephen J.
Rhodopsin Molecular Evolution in Mammals Inhabiting Low Light Environments
title Rhodopsin Molecular Evolution in Mammals Inhabiting Low Light Environments
title_full Rhodopsin Molecular Evolution in Mammals Inhabiting Low Light Environments
title_fullStr Rhodopsin Molecular Evolution in Mammals Inhabiting Low Light Environments
title_full_unstemmed Rhodopsin Molecular Evolution in Mammals Inhabiting Low Light Environments
title_short Rhodopsin Molecular Evolution in Mammals Inhabiting Low Light Environments
title_sort rhodopsin molecular evolution in mammals inhabiting low light environments
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2790605/
https://www.ncbi.nlm.nih.gov/pubmed/20016835
http://dx.doi.org/10.1371/journal.pone.0008326
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