Weng, Mao-Lun , Gibby, Mary , Jansen, Robert K. .
A phylogenetic analysis of Pelargonium based on three plastid genes.
Pelargonium, the second largest genus in the Geraniaceae, contains about 280 species, most of which are widely used in horticulture and herbal medicine. Pelargonium is a characteristic genus of Cape Floristic Region (CFR) because most species are distributed in South Africa; only 32 species occur outside this region, 18 in eastern Africa, 8 in Australasia, 2 in Madagascar, 2 in Turkey, and one each on islands of St. Helena and Tristan de Cunha. Previous studies have addressed the phylogeny of Pelargonium using plastid (trnL-F), mitochondrion (nad1), and nuclear (ITS) markers but overlap in taxon sampling was limited with only 21 species represented by all 3 DNA regions. Although three major and two minor clades were resolved within the genus, these studies were very limited in taxon sampling. In order to test the monophyly of previously identified major clades and to further resolve relationships among closely related species within Pelargonium, expanded taxon sampling was performed for three chloroplast protein-coding genes (rbcL, matK, and ndhF). Phylogenies for 61 species of Pelargonium and 7 outgroups from Geraniales using DNA sequences of these three genes show sufficient variation to resolve phylogenetic relationships. Phylogenetic analyses using maximum parsimony, maximum likelihood, and Bayesian inference provide strong support for the monophyly of most of the clades identified in previous studies (i.e. clades A2, B, C1, and C2). The one exception is clade A2, which is polytomy within the A clade. In addition, the added taxon sampling provides an excellent phylogenetic framework for addressing biogeography, chromosome number evolution, and reconstruction of the evolutionary events leading to the massive plastid genome reorganization in this genus.
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1 - The University of Texas at Austin, Plant Biology, 1 University Station A6720 , Austin, TX, 78712, USA
2 - Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh, EH3 5LR, United Kingdom
Presentation Type: Poster:Posters for Sections
Location: Hall A/Convention Center
Date: Monday, August 2nd, 2010
Time: 5:30 PM