Molecular Ecology and Evolution
Guest, Heidi J. .
Molecular phylogeography of Rhodiola integrifolia Raf. (Crassulaceae) and its postglacial recolonization of north-western North America.
RHODIOLA integrifolia is an arctic/alpine plant species found at higher latitudes from north-western North America to north-eastern Asia and at adjacent higher altitudes further south on both continents. Few phylogeographical analyses have focused exclusively on plants with this amphi-beringian distribution. The range of suitable habitat for alpine and arctic plants has expanded and contracted cyclically during the Quarternary period, last expanding from glacial refugia, such as Beringia, about 18,000 years ago. Founder effects that occur along the leading edges of expanding speciesí ranges can influence genetic diversity of populations as distance from refugia increases. Patterns of genetic heterogeneity can therefore be used to trace the pattern of dispersal and expansion into a new range. I used restriction fragment length polymorphisms (RFLPs) within the non-coding PsbA-trnH spacer region of the chloroplast DNA to explore the distribution of genetic diversity among and within populations of R. integrifolia. Digests with three restriction enzymes (ApoI, BstXI and MseI), uncovered 10 haplotypes among populations from sites in Alaska, Yukon, northern British Columbia, and south of the glacial maximum. Of these, two haplotypes are widely distributed across the region sampled, occurring both within and outside the Beringian refugium. Two haplotypes are more localized in the Yukon and northern BC and occur in previously glaciated areas. Six are single-site haplotypes, three occurring within Beringia, and three in glaciated regions. Of the 45 populations sampled for this study, eight appear to have more than one haplotype present, but these are not distributed in a specific region. By investigating relationships among haplotypes and relating these to the geological history of the region I hope to determine where R. integrifolia populations persisted during the most recent glaciation, and their pattern of spread since the ice retreated.
Log in to add this item to your schedule
1 - University of Victoria, Department of Biology, P.O. Box 3020 STN CSC, Victoria, British Columbia, V8W 3N5, Canada
Presentation Type: Poster:Posters for Topics
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM