Systematics Section / ASPT
Burns, Jean H. , Faden, Robert B. .
Phylogeny of Commelina (Commelinaceae): preliminary results.
As part of a Ph.D. study on the properties of invasive species, using examples from Commelinaceae, a molecular phylogeny of various Commelinaceae was undertaken, stressing those genera from which invasive species and noninvasive related species were investigated. One such genus was Commelina, of which 22 species were used. Both chloroplast (trnL-trnF intergenic spacer) and nuclear (nuclear transcribed spacer region (NTS) of 5S rDNA) sequences were used. A combined analysis of the two sequences yielded a tree with Commelina well supported as monophyletic. The Commelina clade contains a clade of nine species with free spathe margins that arises within the fused-margin spathe grade. The free-margin clade includes taxa with various flower colors from Africa, Asia, North and South America. A clade of seven blue-flowered African species, four also extending beyond mainland Africa, is sister to the remainder of Commelina. Among these seven the species with basic chromosome numbers of x = <15 represent a terminal branch in the clade, indicating that a reduction in basic chromosome number has occurred perhaps only once within the clade. Branch lengths at the base of the Commelina clade are short, suggesting either a rapid diversification, or the absence in the data set of a DNA region evolving at a rate adequate to estimate these branch lengths.
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1 - Tyson Reseach Center, Washington University St. Louis, Biology, Box 1229, 1 Brookings Drive, St. Louis, MO, 63130, U.S.A.
2 - Smithsonian Institution, Department of Botany MRC 166, National Museum Of Natural History, Po Box 37012, Washington, DC, 20560-0166, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Stevens 3/Hilton
Date: Monday, July 9th, 2007
Time: 2:15 PM