Recent Topics Posters
Knope, Matthew .
Recent, rapid adaptive radiation of Hawaiian Bidens (Asteraceae).
Much of biodiversity is thought to emerge through adaptive radiation, the diversification of species to fill a variety of ecological niches. The 19 species of flowering plants in the genus Bidens endemic to the Hawaiian Archipelago are considered one of the best examples of adaptive radiation, yet no molecular phylogenetic hypothesis has been generated for this clade, preventing quantitative assessment of the rate and age of the radiation. This study seeks to determine their phylogenetic history, using four chloroplast and one nuclear DNA marker that have been found particularly useful for reconstructing recent plant radiations. Approximately 4600 base pairs were sequenced per individual. Despite such comprehensive survey, neighbor-joining and maximum parsimony analyses found little genetic variation across these morphologically and ecologically divergent species. These results suggest that the adaptive radiation has been recent and rapid. The most plausible alternative explanation is that rates of molecular evolution in these markers are extremely slow in this radiation. Further, evidence suggests that Hawaiian Bidens are a monophyletic assemblage. Overall, this study indicates that Hawaiian Bidens may be among the most rapid plant adaptive radiations ever studied.
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1 - University of Hawaii, Manoa, Zoology, 2538 McCarthy Mall, Edmondson 152, Honolulu, HI, 96815, USA
Presentation Type: Recent Topics Poster
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM