Systematics Section / ASPT
Tank, David , Olmstead, Richard .
Evolutionary history of perennial Castilleja (Castillejinae, Orobanchaceae): evidence from the nuclear gene waxy.
PERENNIAL Castilleja are a morphologically and taxonomically complex group. This stems from complex morphological variation often attributed to the formation of polyploid complexes, where apparent hybrid swarms and morphological intergradation are common between some species. Molecular phylogenetic analysis of chloroplast and nuclear ribosomal DNA regions indicate that the perennial Castilleja clade (~160 spp.) is derived from a grade of annual Castillejinae taxa, including annual Castilleja species, Cordylanthus, Orthocarpus, and Triphysaria, suggesting that perenniality (restricted to Castilleja) evolved once from an annual ancestor. Significant shifts in diversification rate and short branch length estimates indicate that the perennial Castilleja clade has undergone a rapid and recent diversification. From the chloroplast and nuclear ribosomal DNA results, it was clear that more variable data would be needed to investigate the evolutionary history of species within the perennial Castilleja clade. We present phylogenetic analyses of the nuclear gene waxy, with an emphasis on the evolutionary history of the perennial Castilleja clade, including interspecific relationships, lineage sorting, and hybridization.
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1 - University of Washington, Department of Biology, Box 355325, Seattle, Washington, 98195-5325, USA
Presentation Type: Oral Paper:Papers for Sections
Location: 144/Performing Arts Center
Date: Tuesday, August 1st, 2006
Time: 4:30 PM