Systematics Section / ASPT
Tank, David C. , 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. Here we present phylogenetic analyses of the 3’ portion of the nuclear gene waxy, with an emphasis on the evolutionary history of the perennial Castilleja clade.Â Evolutionary processes including lineage sorting and hybridization, in addition to implications for infrageneric classification of this taxonomically challenging group are discussed.
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1 - Yale University, Peabody Museum of Natural History, Botany Division, P.O. Box 208118, New Haven, CT, 06520-8118, USA
2 - University of Washington, Department of Biology and Burke Museum, Box 355325, Seattle, WA, 98195, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Stevens 2/Hilton
Date: Tuesday, July 10th, 2007
Time: 11:15 AM