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Reproductive mode and genetic variation suggest a North American origin of European Letharia vulpina

Authors

  • Nils Högberg,

    Corresponding author
    1. Department of Plant and Microbial Biology, University of California, Berkeley CA, 94720–3102, USA,
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    • These authors contributed equally to this work.

    • §

      Present address: Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, PO Box 7026, SE-750 07 Uppsala, Sweden.

  • Scott Kroken,

    1. Department of Plant and Microbial Biology, University of California, Berkeley CA, 94720–3102, USA,
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    • These authors contributed equally to this work.

    • Present address: Torrey Mesa Research Institute, 3115 Merryfield Row, Suite 100, San Diego, CA, 92121–1125, USA.

  • Göran Thor,

    1. Department of Conservation Biology, Swedish University of Agricultural Sciences, PO Box 7002, SE-750 07 Uppsala, Sweden
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  • John W. Taylor

    1. Department of Plant and Microbial Biology, University of California, Berkeley CA, 94720–3102, USA,
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Nils Högberg. Fax: + 46 18 309245; E-mail: nils.hogberg@mykopat.slu.se

Abstract

Our data on the intercontinental population biology of Letharia vulpina show an unexpected shift from a recombining North American population with unique haplotypes to genetically depauperate Swedish and Italian populations, each with many representatives of a single repeated haplotype. Analysis of eight loci in 47 individuals supported recombination in North American populations and showed almost no variation among European populations. We infer that a genetic bottleneck caused by limited long-distance dispersal accounts for the lack of genetic variation found in marginal populations. This lack of variation in the European populations makes it impossible to use population genetic means to distinguish clonal reproduction from self-fertilization or even outcrossing, but phenotype indicates that reproduction in the marginal populations is by clonal spread, via soredia and isidioid soredia.

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