Glacial refugia of limber pine (Pinus flexilis James) inferred from the population structure of mitochondrial DNA

Authors

  • J. B. Mitton,

    Corresponding author
    1. Department of Environmental, Population and Organismic Biology, University of Colorado, Boulder, CO 80309, USA,
      J. Mitton, Campus Box 334, University of Colorado, Boulder, CO 80309, USA. Fax: +303-4928699; E-mail:Mitton@Colorado.edu
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  • B. R. Kreiser,

    1. Department of Environmental, Population and Organismic Biology, University of Colorado, Boulder, CO 80309, USA,
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  • R. G. Latta

    1. Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4J1
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J. Mitton, Campus Box 334, University of Colorado, Boulder, CO 80309, USA. Fax: +303-4928699; E-mail:Mitton@Colorado.edu

Abstract

To make inferences about the glacial refugia that harboured the limber pine, Pinus flexilis James, we examined the range-wide population structure of mitochondrial DNA (mtDNA) with eight size variants in the second intron of nad1. The data consisted of haplotypes from 704 trees collected from 40 localities. The value of FST for these populations was 0.80, which is a much larger value than has been reported for allozymes and chloroplast DNA (cpDNA) in limber pine, and it suggests that the number of seeds moving among localities per generation is ≈ 0.12. Gene flow of this magnitude would allow mutation and subsequent genetic drift to have a substantial impact on the population structure of mtDNA. The majority of the mtDNA haplotypes are restricted to minor portions of the geographical range. The data are consistent with mtDNA differentiation in seven glacial refugia, followed by dispersal out of those refugia.

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