Evidence for shared ancestral polymorphism rather than recurrent gene flow at microsatellite loci differentiating two hybridizing oaks (Quercus spp.)

Authors

  • GRAHAM MUIR,

    1. Institut für Tierzucht und Genetik, Veterinärmedizinische Universität Wien, Josef Baumann Gasse 1, 1210, Wien, Austria
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      Present address: School of Biosciences, University of Birmingham, Birmingham, BI5 2TT, UK.

  • CHRISTIAN SCHLÖTTERER

    Corresponding author
    1. Institut für Tierzucht und Genetik, Veterinärmedizinische Universität Wien, Josef Baumann Gasse 1, 1210, Wien, Austria
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Christian Schlötterer, Fax: + 43 1 25077 5693; E-mail: Christian.Schloetterer@vu-wien.ac.at

Abstract

Quercus petraea and Quercus robur are two closely related oak species, considered to hybridize. Genetic markers, however, indicate that despite sharing most alleles, the two species remain separate genetic units. Analysis of 20 microsatellite loci in multiple populations from both species suggested a genome-wide differentiation. Thus, the allele sharing between both species could be explained either by low rates of gene flow or shared ancestral variation. We performed further analyses of population differentiation in a biogeographical setting and an admixture analysis in mixed oak stands to distinguish between both hypotheses. Based on our results we propose that the low genetic differentiation among these species results from shared ancestry rather than high rates of gene flow.

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