Species distribution and introgressive hybridization of two Avicennia species from the Western Hemisphere unveiled by phylogeographic patterns

BMC Evolutionary Biology

Research Article

Gustavo M Mori¹  Anete P Souza²  Maria I Zucchi³  Iracilda Sampaio⁴ 

[1] Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, CEP 13083-875, CP 6010, Campinas, São Paulo, Brazil;Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, CEP 13083-875, CP 6010, Campinas, São Paulo, Brazil;Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, CEP 13083-862, Campinas, São Paulo, Brazil;Pólo Centro Sul, Agência Paulista de Tecnologia dos Agronegócios. Piracicaba, CEP 13400-970, São Paulo, Brazil;Universidade Federal do Pará, Campus de Bragança, Instituto de Estudos Costeiros, CEP 68600-000, Bragança, Pará, Brazil;

关键词: Phylogeography;    Introgression;    cpDNA;    nDNA;    Transoceanic dispersal;   

DOI  :  10.1186/s12862-015-0343-z

 received in 2014-10-07, accepted in 2015-03-30,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundMangrove plants grow in the intertidal zone in tropical and subtropical regions worldwide. The global latitudinal distribution of the mangrove is mainly influenced by climatic and oceanographic features. Because of current climate changes, poleward range expansions have been reported for the major biogeographic regions of mangrove forests in the Western and Eastern Hemispheres. There is evidence that mangrove forests also responded similarly after the last glaciation by expanding their ranges. In this context, the use of genetic tools is an informative approach for understanding how historical processes and factors impact the distribution of mangrove species. We investigated the phylogeographic patterns of two Avicennia species, A. germinans and A. schaueriana, from the Western Hemisphere using nuclear and chloroplast DNA markers.ResultsOur results indicate that, although Avicennia bicolor, A. germinans and A. schaueriana are independent lineages, hybridization between A. schaueriana and A. germinans is a relevant evolutionary process. Our findings also reinforce the role of long-distance dispersal in widespread mangrove species such as A. germinans, for which we observed signs of transatlantic dispersal, a process that has, most likely, contributed to the breadth of the distribution of A. germinans. However, along the southern coast of South America, A. schaueriana is the only representative of the genus. The distribution patterns of A. germinans and A. schaueriana are explained by their different responses to past climate changes and by the unequal historical effectiveness of relative gene flow by propagules and pollen.ConclusionsWe observed that A. bicolor, A. germinans and A. schaueriana are three evolutionary lineages that present historical and ongoing hybridization on the American continent. We also inferred a new evidence of transatlantic dispersal for A. germinans, which may have contributed to its widespread distribution. Despite the generally wider distribution of A. germinans, only A. schaueriana is found in southern South America, which may be explained by the different demographic histories of these two species and the larger proportion of gene flow produced by propagules rather than pollen in A. schaueriana. These results highlight that these species responded in different ways to past events, indicating that such differences may also occur in the currently changing world.

【 授权许可】

Unknown   
© Mori et al.; licensee BioMed Central. 2015. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.