Systematics/Phytogeography / Taxonomie/ Section
Kim, Young-Dong , Kim, Sung-Hee , Shin, Hyunchur .
Molecular phylogeny of Astilbe: implications for phylogeography and morphological evolution.
Astilbe (Saxifragaceae) is a well known genus for its disjunct distribution between Asia and eastern North America. In this study, we reconstructed a molecular phylogeny of the genus using the sequences of ITS regions of nuclear ribosomal DNA. A total of 17 species representing major lineage of Astilbe and its related taxa were included in the phylogenetic analyses. We obtained a single most parsimonious tree in which Saxifragopsis was positioned as a sister group to Astilbe. A Japanese endemic species, A. platyphylla was the most basal lineage within the genus. The species is exhibiting distinct morphological characters such as unisexual flowers, apetaly, and calyx with 7-11 lobes. A. biternata, a New World representative of the genus, was grouped with A. rivularis which distributes mainly in China. The remaining species formed a strongly supported core clade, which diverged into two robust geographical groups, one with the species distributed in Japan, Taiwan, and Philippines and the other consisted of taxa in China and Korea. The ITS phylogeny indicates that both the North Atlantic and the Bering land bridges were involved in the evolution of Astilbe. Taiwanese and Philippine taxa were derived from the Japanese member, as the genus advanced southwards in Asia. The ITS phylogeny suggests that apetaly originated independently at least two times within the genus. Englerís classification system for the genus based on the leaf type (simple vs. compound) was not supported from the ITS tree.
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1 - Hallym University, Department of Life Science, Chuncheon, Gangwon, 200-702, S. Korea
2 - Hallym University, Institute of Natural Sciences, Chuncheon, Gangwon, 200-702, S. Korea
3 - Soonchunhyang University, Department of Biology, Asan, Chungnam, 336-745, S. Korea
Presentation Type: Poster:Posters for Sections
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM