Levsen, Nicholas , Mort, Mark E. .
The Iowa Driftless Area: its role in the ice-age survival and post-glacial recolonization of the boreal forest species Chrysosplenium iowense (Saxifragaceae).
Chrysosplenium iowense (Saxifragaceae) is a southern Canadian boreal forest species with disjunct populations occurring sparsely in the Driftless Area of northeastern Iowa and southeastern Minnesota. The nature of this distribution is the result of relatively recent glacial episodes, but the centers of postglacial recolonization for this species have not yet been identified. While the Driftless Area, known to be a prominent glacial refugium, is a prime candidate for this role, current Canadian populations of C. iowense could be derived from refuges in the Canadian Rockies or from the expansive southern refuge in the central United States. We used Inter-Simple Sequence Repeats (ISSRs), in combination with geographic data, to determine patterns of genetic variation within C. iowense and identify source areas of postglacial recolonization. Results from FST and Monmonier analyses suggest that Canadian populations have been isolated from Iowan populations since before the last glacial maximum, and thus were not recently derived from Driftless Area populations. While source populations for recolonization are expected to exhibit relatively higher levels of genetic diversity and/or allelic richness, estimates of expected heterozygosity and private allele counts were unable to identify any such population(s). This study describes the population genetic structure of a regionally endangered relict species and is one of the first to assess the role of the Driftless Area in postglacial recolonization of high latitude environments.
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1 - University of Kansas, Department of Ecology & Evolutionary Biology, Natural History Museum and Biodiversity Research Center, 1200 Sunnyside Avenue, Lawrence, Kansas, 66045-7534, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Boulevard B/Hilton
Date: Monday, July 9th, 2007
Time: 8:15 AM