| Abstract Detail
Systematics Section / ASPT Allen, Geraldine A. [1], Marr, Ken L. [2], Hebda, Richard J. [2]. Phylogeography of Oxyria digyna (Polygonaceae): implications for glacial history of western North America. Patterns of genetic variation in plant populations reflect both current and historical influences, and provide insight into how these populations may have migrated in response to past climate changes and geological events. We estimated genetic diversity and genetic divergence in 87 populations of the circumboreal Arctic-alpine plant Oxyria digyna (L.) Hill, using restriction site variation in the psbA-trnH and trnT-trnL spacer regions of the chloroplast genome. Pronounced north-south differences in haplotype composition occur in western North American populations of O. digyna. Of the 10 chloroplast haplotypes identified, three are predominantly or entirely northern (north of 56° N). The most northerly of these is widely distributed, occurring also in Norway, Russia, and the Canadian Arctic. Three other haplotypes are largely southern (central British Columbia and southward). At least two haplotypes occur entirely within the boundaries of the last, Late Wisconsin glacial advance. Regional haplotype diversity is greatest in north-central B.C., a region of great topographic relief widely believed to have been fully covered by Late Wisconsin glaciers. The distribution of haplotypes of O. digyna is consistent with postglacial recolonization of B.C. from wide-ranging populations in unglaciated Beringia and the northwest continental United States, but also suggests that populations of O. digyna persisted in several inland and coastal refugia within the Cordilleran Ice sheet.
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1 - University of Victoria, Department of Biology, Po Box 3020 Stn Csc, Victoria, British Columbia, V8W 3N5, Canada
2 - Royal British Columbia Museum, Natural History Section, 675 Belleville Street, Victoria, British Columbia, V8W 9W2, Canada
Keywords:
Phylogeography
Postglacial Migration
Oxyria
psbA-trnH
trnT-trnL
western North America.
Presentation Type: Oral Paper
Session: 25-8
Location: 410/Hilton
Date: Tuesday, August 16th, 2005
Time: 10:15 AM
Abstract ID:447 |
