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International Journal of Ecology
Volume 2012 (2012), Article ID 273413, 10 pages
http://dx.doi.org/10.1155/2012/273413
Research Article

Synergy between Allopatry and Ecology in Population Differentiation and Speciation

1School of Biological Sciences, Bangor University, Bangor LL57 2UW, UK
2Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95064, USA
3Department of Biosciences, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland
4School of Biological Sciences, College of Natural Sciences, Bangor University, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK

Received 19 July 2011; Revised 23 September 2011; Accepted 26 October 2011

Academic Editor: Andrew Hendry

Copyright © 2012 Yann Surget-Groba et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The general diversity pattern of the Caribbean anole radiation has been described in detail; however, the actual mechanisms at the origin of their diversification remain controversial. In particular, the role of ecological speciation, and the relative importance of divergence in allopatry and in parapatry, is debated. We describe the genetic structure of anole populations across lineage contact zones and ecotones to investigate the effect of allopatric divergence, natural selection, and the combination of both factors on population differentiation. Allopatric divergence had no significant impact on differentiation across the lineage boundary, while a clear bimodality in genetic and morphological characters was observed across an ecotone within a single lineage. Critically, the strongest differentiation was observed when allopatry and ecology act together, leading to a sharp reduction in gene flow between two lineages inhabiting different habitats. We suggest that, for Caribbean anoles to reach full speciation, a synergistic combination of several historical and ecological factors may be requisite.