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A. pavia |
PROJECT:
Re-evaluation of the phylogeny and biogeography of the buckeye genus (Aesculus; Hippocastanaceae) with molecular and fossil data - Implications in evolution of phytochemicals of enthonobotanical importance
Phylogeny and biogeography of the buckeye genus (Aesculus; Sapindaceae) – a reevaluation with broader sampling, new method of phylogenetic dating, and new fossil evidence. --BSA 2006 Abstract
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Aesculus is comprised of 13-19 tree and shrub species native to eastern and western North America, East Asia and Europe. Conflicting biogeographic hypotheses have been proposed for the genus based on phylogenetic analyses of molecular and morphological data. Xiang and colleagues (1998) suggested that Aesculus evolved in eastern Asia during the transition of Cretaceous to Tertiary. This finding was based on molecular data from the ITS and matK sites. Contrarily, Forest and collaborators (2001) favored a western North American origin based on the morphological data. The ITS and matK data of Xiang et al. also suggested conflicting placements of the western North American species, A. californica, in the cpDNA and nuclear DNA phylogenies. Recently, Manchester (2001) reported Paleocene fossil leaves and fruits of Aesculus from western North America, Aesculus hickeyi Manchester. This new fossil species has a potential impact on the biogeographic inference. In the present study, we increased sampling of taxa (especially of A. californica) and characters and integrated fossil, morphology, and molecular data from five regions to reconstruct a more robust phylogeny. Our goal is to test the ancestral polymorphism and lineage sorting hypothesis proposed by Xiang et al., and to reexamine the biogeographic history of Aesculus using improved biogeographic and divergence time dating methods.
Publications:
Harris, AJ and QY(J) Xiang, 2009. Estimating ancestral distributions of
lineages with uncertain sister groups: a statistical approach to
dispersal-vicariance analysis and a case using Aesculus L. (Sapindaceae)
including fossils. Journal of Systematics and Evolution. 47: 349-368.
Harris* AJ, QY(J) Xiang, and David Thomas. 2009. Molecular and Morphological
Inference of the Phylogeny, Origin, and Biogeographic History of Aesculus L.
(Sapindaceae or Hippocastanaceae). TAXON 58:1-19.
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