Systematics Section / ASPT
Frasier, Cynthia , Struwe, Lena .
A glimpse into the family tree of Strychnos (Loganiacecae) using ITS sequences.
STRYCHNOS, a member of Loganiaceae, consists of an estimated 200 species that are pantropically distributed. These plants grow as small trees or lianas and have characteristic Melastomataceae-like leaves that have three to five major veins splitting at the base. Strychnos has been used as a component of curare, a dart poison, and to treat numerous ailments from snakebites to gastrointestinal disorders. Past work on Strychnos has been focused primarily on morphology, which has resulted in its division into 12 sections. Over 90 sequences of the internal transcribed spacer (ITS) regions of the nuclear ribosomal DNA were collected, aligned using the secondary structure, and analyzed to reveal the phylogenetic relationships within Strychnos and between other members of Strychneae (Gardneria and Neuburgia). Parsimony and Bayesian analyses of ITS data show that Strychneae is monophyletic, but the sister relationships between genera are unclear as they are united in a polytomy. Strychnos is also monophyletic, as are the African sections Spinosae and Dolichanthae. Nine sections are not supported by ITS data and one monotypic section is not included in the analysis. The most basal Strychnos species are African and there are multiple instances of dispersal from Africa to Asia and from Africa to the Americas. The relationships among American species of Strychnos are not well resolved using ITS sequences. ITS structural features conserved between Strychneae members will also be briefly discussed.
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1 - Rutgers University, Department Plant Biology & Pathology, 237 Foran Hall, 59 Dudley Road, New Brunswick, New Jersey, 08901, USA
2 - Rutgers University, Ecology, Evolution, & Natural Resources, 14 College Farm Rd, New Brunswick, New Jersey, 08901, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Wednesday, August 2nd, 2006
Time: 10:30 AM