Phylogeography of northern North America with insights from paleontological, geological, and molecular data
Allen, Geraldine A. , Marr, Ken L. , Guest, Heidi J. , Elwell, Sherri , Hebda, Richard J. .
Phylogeography of arctic-alpine plants and the glacial history of western North America.
Phylogeographic patterns in plant populations can provide important insights into past climate changes and geological events. We used DNA sequence data from plastid spacer regions to examine these patterns in three arctic-alpine plant species (Oxyria digyna, Rhodiola integrifolia, and Silene acaulis) thought to have been early colonizers of the postglacial landscape in western North America. We observed haplotype relationships and patterns of genetic diversity that were generally consistent with the hypothesized glacial history of the region, including (1) high diversity of haplotypes in unglaciated areas and (2) genetic differentiation between northern and more southern populations. Arctic-alpine species appear to have recolonized the glaciated regions of western North America both from unglaciated Beringia and from unglaciated regions south of the Cordilleran Ice Sheet. However, our results suggest that pathways of postglacial migration in these species have been complex, with some regions receiving multiple influxes of immigrants. Observations of endemic taxa and disjunct populations of species in several localities along the coast of British Columbia have led to proposals of ice-free refugia within the Cordilleran Ice Sheet. Our data are consistent with the persistence of some populations in coastal or inland refugia. We found higher haplotype diversity than expected within some formerly glaciated regions, including haplotypes not found elsewhere.
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1 - University of Victoria, Department of Biology, P.O. 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
plastid sequence data
western North America.
Presentation Type: Symposium or Colloquium Presentation
Location: Room 4/Woodward
Date: Monday, July 28th, 2008
Time: 11:00 AM