Historical demographic dynamics underlying local adaptation in the presence of gene flow

Authors

  • Ângela M. Ribeiro,

    Corresponding author
    1. Museum of Vertebrate Zoology, Department of Integrative Biology, University of California, Berkeley, California, USA
    • Percy FitzPatrick Institute, DST/NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa
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  • Ricardo J. Lopes,

    1. CIBIO Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Universidade do Porto, Vairão, Portugal
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  • Rauri C. K. Bowie

    1. Percy FitzPatrick Institute, DST/NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa
    2. Museum of Vertebrate Zoology, Department of Integrative Biology, University of California, Berkeley, California, USA
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  • FCT (Portugal) and NRF (South Africa).

Correspondence

Ângela M. Ribeiro, Percy FitzPatrick Institute, DST/NRF Centre of Excellence, University of Cape Town, Rondebosch 7701, South Africa. Tel: 001 510 642 3567; Fax: 001 510 642 6984; E-mail: ribeiro.angela@gmail.com

Abstract

The range of a species is the result of the relative contribution of spatial tracking of environmental requirements and adaptation to ecological conditions outside the ancestral niche. The appearance of novel habitats caused by climatic oscillation can promote range expansion and accompanying demographic growth. The demographic dynamics of populations leave a signal in \ patterns. We modeled three competing scenarios pertaining to the circumstance of a range expansion by the Karoo Scrub-Robin into newly available habitat resulting from the increasing aridification of southern Africa. Genetic variation was contrasted with the theoretical expectations of a spatial range expansion, and compared with data of a putative adaptive trait. We infer that this bird likely colonized the arid zone, as a consequence of adaptive evolution in a small peripheral population, followed by an expansion with recurrent exchange of migrants with the ancestral populations.

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