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Evolutionary analyses of visual opsin genes in frogs and toads: Diversity, duplication, and positive selection
Among major vertebrate groups, anurans (frogs and toads) are understudied with regard to their visual systems, and little is known about variation among species that differ in ecology. We sampled North American anurans representing diverse evolutionary and life histories that likely possess visual s...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
John Wiley and Sons Inc.
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8820127/ https://www.ncbi.nlm.nih.gov/pubmed/35154658 http://dx.doi.org/10.1002/ece3.8595 |
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author | Schott, Ryan K. Perez, Leah Kwiatkowski, Matthew A. Imhoff, Vance Gumm, Jennifer M. |
author_facet | Schott, Ryan K. Perez, Leah Kwiatkowski, Matthew A. Imhoff, Vance Gumm, Jennifer M. |
author_sort | Schott, Ryan K. |
collection | PubMed |
description | Among major vertebrate groups, anurans (frogs and toads) are understudied with regard to their visual systems, and little is known about variation among species that differ in ecology. We sampled North American anurans representing diverse evolutionary and life histories that likely possess visual systems adapted to meet different ecological needs. Using standard molecular techniques, visual opsin genes, which encode the protein component of visual pigments, were obtained from anuran retinas. Additionally, we extracted the visual opsins from publicly available genome and transcriptome assemblies, further increasing the phylogenetic and ecological diversity of our dataset to 33 species in total. We found that anurans consistently express four visual opsin genes (RH1, LWS, SWS1, and SWS2, but not RH2) even though reported photoreceptor complements vary widely among species. The proteins encoded by these genes showed considerable sequence variation among species, including at sites known to shift the spectral sensitivity of visual pigments in other vertebrates and had conserved substitutions that may be related to dim‐light adaptation. Using molecular evolutionary analyses of selection (d(N)/d(S)) we found significant evidence for positive selection at a subset of sites in the dim‐light rod opsin gene RH1 and the long wavelength sensitive cone opsin LWS. The function of sites inferred to be under positive selection are largely unknown, but a few are likely to affect spectral sensitivity and other visual pigment functions based on proximity to previously identified sites in other vertebrates. We also found the first evidence of visual opsin duplication in an amphibian with the duplication of the LWS gene in the African bullfrog, which had distinct LWS copies on the sex chromosomes suggesting the possibility of sex‐specific visual adaptation. Taken together, our results indicate that ecological factors, such as habitat and life history, as well as behavior, may be driving changes to anuran visual systems. |
format | Online Article Text |
id | pubmed-8820127 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | John Wiley and Sons Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-88201272022-02-11 Evolutionary analyses of visual opsin genes in frogs and toads: Diversity, duplication, and positive selection Schott, Ryan K. Perez, Leah Kwiatkowski, Matthew A. Imhoff, Vance Gumm, Jennifer M. Ecol Evol Research Articles Among major vertebrate groups, anurans (frogs and toads) are understudied with regard to their visual systems, and little is known about variation among species that differ in ecology. We sampled North American anurans representing diverse evolutionary and life histories that likely possess visual systems adapted to meet different ecological needs. Using standard molecular techniques, visual opsin genes, which encode the protein component of visual pigments, were obtained from anuran retinas. Additionally, we extracted the visual opsins from publicly available genome and transcriptome assemblies, further increasing the phylogenetic and ecological diversity of our dataset to 33 species in total. We found that anurans consistently express four visual opsin genes (RH1, LWS, SWS1, and SWS2, but not RH2) even though reported photoreceptor complements vary widely among species. The proteins encoded by these genes showed considerable sequence variation among species, including at sites known to shift the spectral sensitivity of visual pigments in other vertebrates and had conserved substitutions that may be related to dim‐light adaptation. Using molecular evolutionary analyses of selection (d(N)/d(S)) we found significant evidence for positive selection at a subset of sites in the dim‐light rod opsin gene RH1 and the long wavelength sensitive cone opsin LWS. The function of sites inferred to be under positive selection are largely unknown, but a few are likely to affect spectral sensitivity and other visual pigment functions based on proximity to previously identified sites in other vertebrates. We also found the first evidence of visual opsin duplication in an amphibian with the duplication of the LWS gene in the African bullfrog, which had distinct LWS copies on the sex chromosomes suggesting the possibility of sex‐specific visual adaptation. Taken together, our results indicate that ecological factors, such as habitat and life history, as well as behavior, may be driving changes to anuran visual systems. John Wiley and Sons Inc. 2022-02-07 /pmc/articles/PMC8820127/ /pubmed/35154658 http://dx.doi.org/10.1002/ece3.8595 Text en © 2022 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. https://creativecommons.org/licenses/by/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Research Articles Schott, Ryan K. Perez, Leah Kwiatkowski, Matthew A. Imhoff, Vance Gumm, Jennifer M. Evolutionary analyses of visual opsin genes in frogs and toads: Diversity, duplication, and positive selection |
title | Evolutionary analyses of visual opsin genes in frogs and toads: Diversity, duplication, and positive selection |
title_full | Evolutionary analyses of visual opsin genes in frogs and toads: Diversity, duplication, and positive selection |
title_fullStr | Evolutionary analyses of visual opsin genes in frogs and toads: Diversity, duplication, and positive selection |
title_full_unstemmed | Evolutionary analyses of visual opsin genes in frogs and toads: Diversity, duplication, and positive selection |
title_short | Evolutionary analyses of visual opsin genes in frogs and toads: Diversity, duplication, and positive selection |
title_sort | evolutionary analyses of visual opsin genes in frogs and toads: diversity, duplication, and positive selection |
topic | Research Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8820127/ https://www.ncbi.nlm.nih.gov/pubmed/35154658 http://dx.doi.org/10.1002/ece3.8595 |
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