Evolution of biogeographic patterns, ploidy levels, and breeding systems in a diploid–polyploid species complex of Primula

Authors

  • Alessia Guggisberg,

    1. Institut für Systematische Botanik, Universität Zürich, Zollikerstrasse 107, CH−8008 Zürich, Switzerland;
    2. Present address: Institut für Systematische Botanik, Universität Zürich, Zollikerstrasse 107, CH−8008 Zürich, Switzerland
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  • Guilhem Mansion,

    1. Institut für Systematische Botanik, Universität Zürich, Zollikerstrasse 107, CH−8008 Zürich, Switzerland;
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  • Sylvia Kelso,

    1. Department of Biology, Colorado College, 14 East Cache La Poudre Street, Colorado Springs, CO 80903, USA;
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  • Elena Conti

    1. Institut für Systematische Botanik, Universität Zürich, Zollikerstrasse 107, CH−8008 Zürich, Switzerland;
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Author for correspondence: Alessia Guggisberg Tel: +41 44 6348430 Fax: +41 44 6348403 Email: alg@systbot.unizh.ch

Summary

  • • Primula sect. Aleuritia subsect. Aleuritia (Aleuritia) includes diploid, self-incompatible heterostyles and polyploid, self-compatible homostyles, the latter generally occurring at higher latitudes than the former. This study develops a phylogenetic hypothesis for Aleuritia to elucidate the interactions between Pleistocene glacial cycles, biogeographic patterns, ploidy levels and breeding systems.
  • • Sequences from five chloroplast DNA loci were analyzed with parsimony to reconstruct a phylogeny, haplotype network, and ancestral states for ploidy levels and breeding systems.
  • • The results supported the monophyly of Aleuritia and four major biogeographic lineages: an amphi-Pacific, a South American, an amphi-Atlantic and a European/North American lineage. At least four independent switches to homostyly and five to polyploidy were inferred.
  • • An Asian ancestor probably gave origin to an amphi-Pacific clade and to a lineage that diversified on the European and American continents. Switches to homostyly occurred exclusively in polyploid lineages, which mainly occupy previously glaciated areas. The higher success of the autogamous polyploid species at recolonizing habitats freed by glacial retreat might be explained in terms of selection for reproductive assurance.

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