Cargando…

Genetic Introgression and Species Boundary of Two Geographically Overlapping Pine Species Revealed by Molecular Markers

Gene introgression and hybrid barriers have long been a major focus of studies of geographically overlapping species. Two pine species, Pinus massoniana and P. hwangshanensis, are frequently observed growing adjacent to each other, where they overlap in a narrow hybrid zone. As a consequence, these...

Descripción completa

Detalles Bibliográficos
Autores principales: Zhang, Defang, Xia, Tao, Yan, Maomao, Dai, Xiaogang, Xu, Jin, Li, Shuxian, Yin, Tongming
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4076219/
https://www.ncbi.nlm.nih.gov/pubmed/24977711
http://dx.doi.org/10.1371/journal.pone.0101106
_version_ 1782323455187746816
author Zhang, Defang
Xia, Tao
Yan, Maomao
Dai, Xiaogang
Xu, Jin
Li, Shuxian
Yin, Tongming
author_facet Zhang, Defang
Xia, Tao
Yan, Maomao
Dai, Xiaogang
Xu, Jin
Li, Shuxian
Yin, Tongming
author_sort Zhang, Defang
collection PubMed
description Gene introgression and hybrid barriers have long been a major focus of studies of geographically overlapping species. Two pine species, Pinus massoniana and P. hwangshanensis, are frequently observed growing adjacent to each other, where they overlap in a narrow hybrid zone. As a consequence, these species constitute an ideal system for studying genetic introgression and reproductive barriers between naturally hybridizing, adjacently distributed species. In this study, we sampled 270 pine trees along an elevation gradient in Anhui Province, China and analyzed these samples using EST-SSR markers. The molecular data revealed that direct gene flow between the two species was fairly low, and that the majority of gene introgression was intermediated by backcrossing. On the basis of empirical observation, the on-site distribution of pines was divided into a P. massoniana zone, a hybrid zone, and a P. hwangshanensis zone. STRUCTURE analysis revealed the existence of a distinct species boundary between the two pine species. The genetic boundary of the hybrid zone, on the other hand, was indistinct owing to intensive backcrossing with parental species. Compared with P. massoniana, P. hwangshanensis was found to backcross with the hybrids more intensively, consistent with the observation that morphological and anatomical characteristics of trees in the contact zone were biased towards P. hwangshanensis. The introgression ability of amplified alleles varied across species, with some being completely blocked from interspecific introgression. Our study has provided a living example to help explain the persistence of adjacently distributed species coexisting with their interfertile hybrids.
format Online
Article
Text
id pubmed-4076219
institution National Center for Biotechnology Information
language English
publishDate 2014
publisher Public Library of Science
record_format MEDLINE/PubMed
spelling pubmed-40762192014-07-02 Genetic Introgression and Species Boundary of Two Geographically Overlapping Pine Species Revealed by Molecular Markers Zhang, Defang Xia, Tao Yan, Maomao Dai, Xiaogang Xu, Jin Li, Shuxian Yin, Tongming PLoS One Research Article Gene introgression and hybrid barriers have long been a major focus of studies of geographically overlapping species. Two pine species, Pinus massoniana and P. hwangshanensis, are frequently observed growing adjacent to each other, where they overlap in a narrow hybrid zone. As a consequence, these species constitute an ideal system for studying genetic introgression and reproductive barriers between naturally hybridizing, adjacently distributed species. In this study, we sampled 270 pine trees along an elevation gradient in Anhui Province, China and analyzed these samples using EST-SSR markers. The molecular data revealed that direct gene flow between the two species was fairly low, and that the majority of gene introgression was intermediated by backcrossing. On the basis of empirical observation, the on-site distribution of pines was divided into a P. massoniana zone, a hybrid zone, and a P. hwangshanensis zone. STRUCTURE analysis revealed the existence of a distinct species boundary between the two pine species. The genetic boundary of the hybrid zone, on the other hand, was indistinct owing to intensive backcrossing with parental species. Compared with P. massoniana, P. hwangshanensis was found to backcross with the hybrids more intensively, consistent with the observation that morphological and anatomical characteristics of trees in the contact zone were biased towards P. hwangshanensis. The introgression ability of amplified alleles varied across species, with some being completely blocked from interspecific introgression. Our study has provided a living example to help explain the persistence of adjacently distributed species coexisting with their interfertile hybrids. Public Library of Science 2014-06-30 /pmc/articles/PMC4076219/ /pubmed/24977711 http://dx.doi.org/10.1371/journal.pone.0101106 Text en © 2014 Zhang 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
Zhang, Defang
Xia, Tao
Yan, Maomao
Dai, Xiaogang
Xu, Jin
Li, Shuxian
Yin, Tongming
Genetic Introgression and Species Boundary of Two Geographically Overlapping Pine Species Revealed by Molecular Markers
title Genetic Introgression and Species Boundary of Two Geographically Overlapping Pine Species Revealed by Molecular Markers
title_full Genetic Introgression and Species Boundary of Two Geographically Overlapping Pine Species Revealed by Molecular Markers
title_fullStr Genetic Introgression and Species Boundary of Two Geographically Overlapping Pine Species Revealed by Molecular Markers
title_full_unstemmed Genetic Introgression and Species Boundary of Two Geographically Overlapping Pine Species Revealed by Molecular Markers
title_short Genetic Introgression and Species Boundary of Two Geographically Overlapping Pine Species Revealed by Molecular Markers
title_sort genetic introgression and species boundary of two geographically overlapping pine species revealed by molecular markers
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4076219/
https://www.ncbi.nlm.nih.gov/pubmed/24977711
http://dx.doi.org/10.1371/journal.pone.0101106
work_keys_str_mv AT zhangdefang geneticintrogressionandspeciesboundaryoftwogeographicallyoverlappingpinespeciesrevealedbymolecularmarkers
AT xiatao geneticintrogressionandspeciesboundaryoftwogeographicallyoverlappingpinespeciesrevealedbymolecularmarkers
AT yanmaomao geneticintrogressionandspeciesboundaryoftwogeographicallyoverlappingpinespeciesrevealedbymolecularmarkers
AT daixiaogang geneticintrogressionandspeciesboundaryoftwogeographicallyoverlappingpinespeciesrevealedbymolecularmarkers
AT xujin geneticintrogressionandspeciesboundaryoftwogeographicallyoverlappingpinespeciesrevealedbymolecularmarkers
AT lishuxian geneticintrogressionandspeciesboundaryoftwogeographicallyoverlappingpinespeciesrevealedbymolecularmarkers
AT yintongming geneticintrogressionandspeciesboundaryoftwogeographicallyoverlappingpinespeciesrevealedbymolecularmarkers