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Strong Selection Against Early Generation Hybrids in Joshua Tree Hybrid Zone Not Explained by Pollinators Alone
Coevolution frequently plays an important role in diversification, but the role of obligate pollination mutualisms in the maintenance of hybrid zones has rarely been investigated. Like most members of the genus Yucca, the two species of Joshua tree (Yucca brevifolia and Yucca jaegeriana) are involve...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Frontiers Media S.A.
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7264850/ https://www.ncbi.nlm.nih.gov/pubmed/32528500 http://dx.doi.org/10.3389/fpls.2020.00640 |
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author | Royer, Anne M. Waite-Himmelwright, Jackson Smith, Christopher Irwin |
author_facet | Royer, Anne M. Waite-Himmelwright, Jackson Smith, Christopher Irwin |
author_sort | Royer, Anne M. |
collection | PubMed |
description | Coevolution frequently plays an important role in diversification, but the role of obligate pollination mutualisms in the maintenance of hybrid zones has rarely been investigated. Like most members of the genus Yucca, the two species of Joshua tree (Yucca brevifolia and Yucca jaegeriana) are involved in a tightly coevolved mutualism with yucca moths. There is strong evidence of a history of coevolution between Joshua trees and their moth pollinators. We use a geographic clines approach in the Joshua tree hybrid zone to ask if selection by the moths may currently contribute to maintaining separation between these species. We compare genomic, phenotypic, and pollinator frequency clines to test whether pollinators maintain the hybrid zone or follow it as passive participants. The results reveal dramatic overlapping genomic and pollinator clines, consistent with a narrow hybrid zone maintained by strong selection. Wider phenotypic clines and a chloroplast genomic cline displaced opposite the expected direction suggest that pollinators are not the main source of selection maintaining the hybrid zone. Rather, it seems that high levels of reproductive isolation, likely acting through multiple barriers and involving many parts of the genome, keep the hybrid zone narrow. |
format | Online Article Text |
id | pubmed-7264850 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-72648502020-06-10 Strong Selection Against Early Generation Hybrids in Joshua Tree Hybrid Zone Not Explained by Pollinators Alone Royer, Anne M. Waite-Himmelwright, Jackson Smith, Christopher Irwin Front Plant Sci Plant Science Coevolution frequently plays an important role in diversification, but the role of obligate pollination mutualisms in the maintenance of hybrid zones has rarely been investigated. Like most members of the genus Yucca, the two species of Joshua tree (Yucca brevifolia and Yucca jaegeriana) are involved in a tightly coevolved mutualism with yucca moths. There is strong evidence of a history of coevolution between Joshua trees and their moth pollinators. We use a geographic clines approach in the Joshua tree hybrid zone to ask if selection by the moths may currently contribute to maintaining separation between these species. We compare genomic, phenotypic, and pollinator frequency clines to test whether pollinators maintain the hybrid zone or follow it as passive participants. The results reveal dramatic overlapping genomic and pollinator clines, consistent with a narrow hybrid zone maintained by strong selection. Wider phenotypic clines and a chloroplast genomic cline displaced opposite the expected direction suggest that pollinators are not the main source of selection maintaining the hybrid zone. Rather, it seems that high levels of reproductive isolation, likely acting through multiple barriers and involving many parts of the genome, keep the hybrid zone narrow. Frontiers Media S.A. 2020-05-26 /pmc/articles/PMC7264850/ /pubmed/32528500 http://dx.doi.org/10.3389/fpls.2020.00640 Text en Copyright © 2020 Royer, Waite-Himmelwright and Smith. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
spellingShingle | Plant Science Royer, Anne M. Waite-Himmelwright, Jackson Smith, Christopher Irwin Strong Selection Against Early Generation Hybrids in Joshua Tree Hybrid Zone Not Explained by Pollinators Alone |
title | Strong Selection Against Early Generation Hybrids in Joshua Tree Hybrid Zone Not Explained by Pollinators Alone |
title_full | Strong Selection Against Early Generation Hybrids in Joshua Tree Hybrid Zone Not Explained by Pollinators Alone |
title_fullStr | Strong Selection Against Early Generation Hybrids in Joshua Tree Hybrid Zone Not Explained by Pollinators Alone |
title_full_unstemmed | Strong Selection Against Early Generation Hybrids in Joshua Tree Hybrid Zone Not Explained by Pollinators Alone |
title_short | Strong Selection Against Early Generation Hybrids in Joshua Tree Hybrid Zone Not Explained by Pollinators Alone |
title_sort | strong selection against early generation hybrids in joshua tree hybrid zone not explained by pollinators alone |
topic | Plant Science |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7264850/ https://www.ncbi.nlm.nih.gov/pubmed/32528500 http://dx.doi.org/10.3389/fpls.2020.00640 |
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