Systematics Section / ASPT
Barker, Michael S. , Kane, Nolan , Rieseberg, Loren H. .
Widespread paleopolyploidy across the Viridiplantae.
Our understanding of green plant evolution has been revolutionized by the availability and analyses of plant genome data. Perhaps the largest discovery from these analyses is the pervasive role of duplication in plant genome evolution. In particular, recent analyses have demonstrated that numerous flowering plants have experienced ancient genome duplication events, or paleopolyploidy, and that all angiosperms likely have a polyploid ancestry. However, most plant genome analyses to date have focused on model plant species, in particular Arabidopsis, because they have the most available data. We sought to expand our knowledge of paleopolyploidy beyond these well studied organisms using the growing EST resources available for the Viridiplantae. Using a bioinformatic pipeline, we examined nearly 12 million EST sequences representing 260 species of green plants for evidence of ancient genome duplications. We have so far documented 25 independent ancient duplication events distributed across the angiosperms, gymnosperms, monilophytes, and bryophytes. Paleopolyploidy was not observed in any member of the green algae or the lycophytes, although there is a paucity of data for the latter. Our results provide evidence that paleopolyploidy is widespread across land plants, and the number and distribution of ancient duplication events detected in our analyses firmly refute the position that polyploidy is evolutionary noise or a dead end. Further analyses of this phylogenetically broad data set will permit evaluations of previously untestable hypotheses on the role of polyploid speciation in plant evolution.
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1 - University of British Columbia, Department of Botany, 3529-6270 University Blvd., Vancouver, BC, V6T 1Z4, Canada
Presentation Type: Oral Paper:Papers for Sections
Location: International Ballroom South/Hilton
Date: Wednesday, July 11th, 2007
Time: 4:30 PM