Abstract Detail



Biogeography

Kanne, Rande [1], Allen, Geraldine [2].

Phylogeographic patterns and migrational history of Garry oak (Quercus garryana).

Garry oak (Quercus garryana) is a white oak (Quercus sect. Quercus) with a geographic distribution extending from southwestern British Columbia to south-central California. It is the northernmost species of the California-Pacific Northwest white oak clade, and the only native white oak in British Columbia and Washington. We hypothesize that Garry oak migrated northward into its current geographic range following the Last Glacial Maximum. We used chloroplast and nuclear sequence data to address the following questions. 1) What are the patterns of genetic variation within Garry oak?  2) How do these patterns vary geographically, and how did Garry oak come to occupy its current geographical range? 3) Does Garry oak show evidence of genetic interaction with other white oak species in western North America? We collected samples of Garry oak from 117 localities over its geographic range. We also sampled two other California white oaks (Q. lobata and Q. douglasii) and a Rocky Mt. species (Q. gambelii). Analyses from four cpDNA regions revealed 28 plastid haplotypes. These show a strong south-to-north decrease in genetic diversity, consistent with northward spread. Haplotypes present in the northern part of the range provide evidence of two separate northward migrations, only one of which reached the northern range limit of Garry oak. Our results also suggest that Garry oak hybridizes with at least two other white oak species in the southern part of its range. We are in the process of collecting and analyzing nuclear (ribosomal ITS) sequence data and comparing genetic variation among varieties of Garry oak. Our preliminary findings suggest that the three currently recognized varieties of Garry oak (var. garryana, var. breweri and var. semota) are not genetically well differentiated. 


1 - University of Victoria, Department of Biology, PO Box 1700, Station CSC, Victoria, British Columbia, V8W 2Y2, Canada
2 - University Of Victoria, Department Of Biology, PO Box 1700 Station CSC, Victoria, BC, V8W 2Y2, Canada

Keywords:
Quercus garryana
Phylogeography
plastid DNA
ITS
white oaks
Hybridization.

Presentation Type: Poster
Number: PBG008
Abstract ID:664
Candidate for Awards:Ian and Syvia Taylor Award


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