Systematics Section / ASPT
Levsen, Nicholas , Mort, Mark E. .
ISSR variation in Iowa populations of the glacial relict Chrysosplenium iowense (Saxifragaceae).
Chrysosplenium iowense is an herbaceous, boreal forest species primarily distributed throughout southern Canada, though maintaining a narrow distribution in the driftless area of northeastern Iowa where it persists as a Pleistocene glacial relict. In Iowa, C. iowense is endemic to rare algific talus slope environments, which maintain near-ground temperatures at 1-15°C during summer months. In a previous isozyme survey, the Iowa populations of C. iowense have been shown, in a previous study employing enzyme electrophoresis, to exhibit no observable genetic variation. This result, one common to other electrophoretic studies of saxifrages, is presumably attributable to small effective population sizes and lack of gene flow among geographically isolated populations. However, C. iowense also exhibits characteristics that are often associated with higher levels of genetic variation including high ploidy level, with a chromosome number of 2n ~ 120, and obligate outcrossing. Given the often conservative nature of enzyme results as well as the chromosomal patterns, reproductive biology, and putative biogeographic history of C. iowense, I conducted a population genetic study of the species occurring in the driftless area and employed Inter-Simple Sequence Repeats (ISSRs), a hyper-variable DNA method, to determine the genetic structure of populations in that region. Analyses of ISSR data collected from six Iowa populations of C. iowense have revealed observable genetic variation both within and among populations and the data will be used to determine patterns of population genetic structure for this species. Determining the genetic structure of Iowa populations of C. iowense is the first step in reconstructing the glacial population history of the species as well as the continuation of efforts for its conservation in this region.
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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
Date: Monday, August 15th, 2005
Time: 2:15 PM