Systematics Section / ASPT
Pelser, Pieter B. , Kadereit, Joachim W. , Nordenstam, Bertil , Breitwieser, Ilse , Wagstaff, Steven J. , Watson, Linda E. .
Reconstructing the evolutionary history of a giant: a preliminary ITS phylogeny of Senecio and Tribe Senecioneae (Asteraceae).
Tribe Senecioneae (Asteraceae) includes Senecio, one of the largest genera of flowering plants that has a cosmopolitan distribution and is composed of 1,000–3,000 species. This genus harbors remarkable diversity in morphology and life-history strategies and is notorious for its toxic pyrrolizidine alkaloids, secondary metabolites that are an effective chemical defense mechanism against herbivores and are the subject of many ecological and biochemical studies. Systematic studies in Senecio have, however, always been frustrated by its enormous size and the fact that it is, in all likelihood, a polyphyletic assemblage.
To better understand the underlying patterns of diversity and the evolutionary success of Senecio, we are inferring the evolutionary history within the broader context of Tribe Senecioneae using DNA sequence data of the ITS region of nrDNA. Preliminary results for over 300 species sequenced thus far confirm the polyphyletic nature of Senecio, and indicate that some genera assigned to Senecioneae may be more closely related to taxa of other tribes. In addition, the resulting phylogeny brings several interesting global biogeographical patterns to light.
In the near future, we will expand our data set with sequences of several plastid regions and will aim at including representatives of all 143 genera in the tribe and c. 125 sections of Senecio in our phylogenetic analyses.
1 - Miami University, Department of Botany, 316 Pearson Hall, Oxford, Ohio, 45056, USA
2 - Landcare Research, Allan Herbarium, P.O. Box 69, Lincoln, 8152, New Zealand
3 - Swedish Museum of Natural History, Department of Phanerogamic Botany, P.O. Box 50007, Stockholm, SE-104 05, Sweden
4 - Johannes Gutenberg-Universität Mainz, Institut für Spezielle Botanik und Botanischer Garten, Bentzelweg 9a, Mainz, D-55099, Germany
Presentation Type: Poster
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM