Colloquia: Emerging Results from Studies of Gymnosperms on the Tree of Life II
Barker, Michael S. , Graham, Sean W. , Rieseberg, Loren H. .
Comparative gymnosperm transcriptomics.
Transcriptome sequencing provides an increasingly affordable means of generating sequence data sets for the coding regions of plant genomes that are significant for evolutionary and functional studies. These data are especially useful for plants with large and complex genomes, such as most gymnosperms, where genome sequencing costs are still prohibitive. Through various public efforts and our own transcriptome sequencing, gymnosperms are becoming relatively well represented by transcriptome data from most major clades, with transcriptome data now available for 11 genera. Using these data, we have evaluated a number of questions concerning the evolution of gymnosperms. A surprising result of our analyses is that gymnosperms have an estimated rate of genome duplication that is nearly identical to the angiosperms, despite a much lower frequency of extant polyploidy. Further, we find evidence of a whole genome duplication that is shared by Ginkgo, the cycads, and the conifers. Our analyses do not find evidence of this duplication in members of the Gnetales or angiosperms. After accounting for significant substitution rate heterogeneity among the Gnetales and other gymnosperms, pairwise comparisons of gymnosperm clades indicate that this duplication occurred after the divergence of Gnetales from each other lineage. These results suggest that extant seed plants are composed of three extant groups: angiosperms, Gnetales, and the remaining gymnosperms.
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1 - University of British Columbia, The Biodiversity Research Centre, 6270 University Blvd., Vancouver, BC, V6T 1Z4, Canada
2 - University of British Columbia, UBC Botanical Garden and Certre for Plant Research, 6804 SW Marine Drive, Vancouver, BC, V4T 1Z4, Canada
3 - University of British Columbia, Department of Botany, 3529-6270 University Blvd, Vancouver, BC, V6T 1Z4, Canada
Presentation Type: Symposium or Colloquium Presentation
Location: Ballroom C/Convention Center
Date: Monday, August 2nd, 2010
Time: 4:15 PM