Comparative phylogeography among hydrothermal vent species along the East Pacific Rise reveals vicariant processes and population expansion in the South

Authors

  • S. PLOUVIEZ,

    1. Laboratoire Adaptation et Diversité en Milieu Marin, Université Pierre et Marie Curie-Paris 6; and CNRS, UMR7144 Station Biologique de Roscoff, Roscoff, France
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  • T. M. SHANK,

    1. Biology Department MS#33, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
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  • B. FAURE,

    1. Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
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  • C. DAGUIN-THIEBAUT,

    1. Laboratoire Adaptation et Diversité en Milieu Marin, Université Pierre et Marie Curie-Paris 6; and CNRS, UMR7144 Station Biologique de Roscoff, Roscoff, France
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  • F. VIARD,

    1. Laboratoire Adaptation et Diversité en Milieu Marin, Université Pierre et Marie Curie-Paris 6; and CNRS, UMR7144 Station Biologique de Roscoff, Roscoff, France
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  • F. H. LALLIER,

    1. Laboratoire Adaptation et Diversité en Milieu Marin, Université Pierre et Marie Curie-Paris 6; and CNRS, UMR7144 Station Biologique de Roscoff, Roscoff, France
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  • D. JOLLIVET

    1. Laboratoire Adaptation et Diversité en Milieu Marin, Université Pierre et Marie Curie-Paris 6; and CNRS, UMR7144 Station Biologique de Roscoff, Roscoff, France
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  • This study is a component of S.P.’s PhD project, which investigates comparative phylogeography of deep-sea hydrothermal vent species. Her research uses multiple species and markers to examine demographic processes and species dispersion along the East Pacific Rise. The PhD is co-supervised by D.J. and F.H.L. T.M.S. B.F., C.D. and F.V. made significant contributions to this study through the design of sampling strategies, field collections and editing that improved the manuscript, initially written by the first author.

Sophie Plouviez, Fax: +332 988 92324;
E-mail: plouviez@sb-roscoff.fr

Abstract

The use of sequence polymorphism from individual mitochondrial genes to infer past demography has recently proved controversial because of the recurrence of selective sweeps acting over genes and the need for unlinked multilocus data sets. However, comparative analyses using several species for one gene and/or multiple genes for one species can serve as a test for potential selective effects and clarify our understanding of historical demographic effects. This study compares nucleotide polymorphisms in mitochondrial cytochrome oxidase I across seven deep-sea hydrothermal vent species that live along the volcanically active East Pacific Rise. Approximate Bayesian Computation (ABC) method, developed to trace shared vicariant events across species pairs, indicates the occurrence of two across species divergence times, and suggests that the present geographical patterns of genetic differentiation may be explained by two periods of significant population isolation. The oldest period dates back 11.6 Ma and is associated with the vent limpet Lepetodrilus elevatus, while the most recent period of isolation is 1.3 Ma, which apparently affected all species examined and coincides with a transition zone across the equator. Moreover, significant negative Tajima’s D and star-like networks were observed for all southern lineages, suggesting that these lineages experienced a concomitant demographic and geographical expansion about 100 000–300 000 generations ago. This expansion may have initiated from a wave of range expansions during the secondary colonization of new sites along the Southern East Pacific Rise (founder effects below the equator) or recurrent bottleneck events because of the increase of eruptive phases associated with the higher spreading rates of the ridge in this region.

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