Species replacement along a linear coastal habitat: phylogeography and speciation in the red alga Mazzaella laminarioidesalong the south east pacific

BMC Evolutionary Biology

Research Article

Pilar A Haye¹  Bernardo R Broitman²  Florence Tellier³  Sylvain Faugeron⁴  Marie-Laure Guillemin⁵  Alejandro Montecinos⁵ 

[1] Departamento de Biología Marina, Facultad de Ciencias del Mar & Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Universidad Católica del Norte, 1281, Larrondo, Coquimbo, Chile;Departamento de Biología Marina, Facultad de Ciencias del Mar & Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Universidad Católica del Norte, 1281, Larrondo, Coquimbo, Chile;Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, 340, AlamedaSantiago, Chile;Departamento de Biología Marina, Facultad de Ciencias del Mar & Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Universidad Católica del Norte, 1281, Larrondo, Coquimbo, Chile;Departamento de Ecología, Facultad de Ciencias, Universidad Católica de la Santísima Concepción, 297, Casilla, Concepción, Chile;Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, 340, AlamedaSantiago, Chile;Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Campus Isla Teja, 567, Casilla, Valdivia, Chile;

关键词: Phylogeography;    South East Pacific coast;    COI;    rbc;    Red seaweed;    Parapatric distribution;    Sister-species complex;    Pleistocene glaciations;   

DOI  :  10.1186/1471-2148-12-97

 received in 2012-02-25, accepted in 2012-05-24,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundThe Chilean shoreline, a nearly strait line of coast expanding across 35 latitudinal degrees, represents an interesting region to assess historical processes using phylogeographic analyses. Stretching along the temperate section of the East Pacific margin, the region is characterized by intense geologic activity and has experienced drastic geomorphological transformations linked to eustatic and isostatic changes during the Quaternary. In this study, we used two molecular markers to evaluate the existence of phylogeographic discontinuities and detect the genetic footprints of Pleistocene glaciations among Patagonian populations of Mazzaella laminarioides, a low-dispersal benthic intertidal red seaweed that inhabits along ~3,700 km of the Chilean coastal rocky shore.ResultsThree main genetic lineages were found within M. laminarioides. They are distributed along the Chilean coast in strict parapatry. The deep divergence among lineages suggests that they could be considered putative genetic sibling species. Unexpectedly, genetic breaks were not strictly concordant with the biogeographic breaks described in the region. A Northern lineage was restricted to a broad transition zone located between 30°S and 33°S and showed signals of a recent bottleneck. The reduction of population size could be related to warm events linked to El Niño Southern Oscillation, which is known to cause massive seaweed mortality in this region. To the south, we propose that transient habitat discontinuities driven by episodic tectonic uplifting of the shoreline around the Arauco region (37°S-38°S); one of the most active forearc-basins in the South East Pacific; could be at the origin of the Central/South genetic break. The large beaches, located around 38°S, are likely to contribute to the lineages’ integrity by limiting present gene flow. Finally, the Southern lineage, occupies an area affected by ice-cover during the last glaciations. Phylogeny suggested it is a derived clade and demographic analyses showed the lineage has a typical signature of postglacial recolonization from a northern glacial refugium area.ConclusionsEven if environmental adaptation could have strengthened divergence among lineages in M. laminarioides, low dispersal capacity and small population size are sufficient to generate phylogeographic discontinuities determined by genetic drift alone. Interestingly, our results confirm that seaweed population connectivity over large geographic scales does not rely only on dispersal capacity but also seem to depend highly on substratum availability and population density of the receiving locality.

【 授权许可】

Unknown   
© Montecinos et al.; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.