Systematics Section / ASPT
Lee, Joongku , Baldwin, Bruce G. , Davis, William S. , Lee, Hyeong-Kyu .
Molecular phylogenetic perspectives on the evolution and biogeographic history of Malacothrix (Compositae--Cichorieae).
Results from phylogenetic analyses of 18S-26S nrDNA external and internal transcribed spacer (ETS and ITS) sequences from all recognized taxa of Malacothrix (Compositate--Cichorieae) and closely related genera reinforce the conclusion of Lee et al. (2003) that the genus is not monophyletic and allow for a more detailed perspective on relationships, historical biogeography, and character evolution in subtribe Malacothricinae. Based on well-supported nrDNA clades, evolutionary change in reproductive and vegetative characters within Malacothrix has been more dynamic than previously appreciated; for example, exclusion from Malacothrix of taxa long-treated in Anisocoma, Calycoseris, and Atrichoseris was based largely on unusual fruit, pappus, or foliage characteristics that now appear to have been derived from ancestral states shared by members of Malacothrix. Some morphological characteristics, including components of fruit-wall sculpturing, map onto the molecular trees with minimal homoplasy and, in part, account for congruence between membership of nrDNA-based clades and informal species-groups proposed earlier by W. S. Davis. All taxa of Malacothrix that occur in the California Islands belong to one of two nrDNA clades that correspond precisely to Davis's "Malacolepis" and "Malacomeris;" insular members of both groups appear to have descended from self-compatible (SC) ancestors, in accord with Baker's Rule, based on inferred relationships of self-incompatible (SI) and SC taxa in the molecular trees. Combined analysis of molecular and morphological data is being pursued to refine understanding of the evolutionary and biogeographic history of Malacothricinae.
1 - University of California, Berkeley, Jepson Herbarium and Department of Integrative Biology, 1001 Valley Life Sciences Bldg. #2465, Berkeley, California, 94720-2465, USA
2 - Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-333, , South Korea
3 - University of Louisville, Department of Biology, Louisville, Kentucky, 40292, USA
4 - Korea Research Institute of Bioscience and Biotechnology, ,, Daejeon 305-333, , South Korea
nuclear ribosomal DNA
Presentation Type: Poster
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM