Systematics/Phytogeography / Taxonomie/ Section
Russell, Anton , Rupp, Barbara , Safran, Marko , Samuel, Rosabelle , Barfuss, Michael , Klejna, Verena , Schneeweiss, Hanna , Besendorfer, Visnja , Reich, Dieter , Chase, Mark W. .
Molecular systematics of Polystachya (Orchidaceae).
The genus Polystachya Hook. (Orchidaceae, Epidendroideae) contains approximately 240 species distributed in Africa, Asia and the Neotropics, with most species in tropical Africa. The current infrageneric classification system divides the genus into 15 sections based on gross morphology. Its pantropical distribution and high levels of morphological and ecological variation make the genus a good subject for evolutionary studies.
We are compiling plastid DNA sequences from the rps16-trnK-matK region and ITS nuclear rDNA, as part of a genus-wide study of Polystachya systematics. In addition, we are gathering data on chromosome number and genome size to investigate genome evolution. It seems that polyploidisation was important in the evolution of some lineages.
Data so far suggest the genus falls into five main clades correlating with morphological and biogeographical trends. There are some additional basal lineages with a smaller number of species. One part of the genus has a primarily east-central African distribution with some species ranges extending more widely; another is primarily west-central African. The widespread section Polystachya is poorly resolved and has undergone recent intercontinental dispersal. Future work includes analysis of low-copy nuclear genes to investigate the role of reticulate evolution in the genus, and population genetic analysis on some closely related Neotropical species to look at patterns of genetic diversity and gene flow.
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1 - University of Vienna, Department of Systematic and Evolutionary Botany, Faculty of Life Sciences, Rennweg 14, Vienna, A-1030 Vienna, Austria
2 - University of Zagreb, Department of Molecular Biology, Horvatovac 102a, Zagreb, HR-10000 Zagreb, Croatia
3 - University of Vienna, Faculty Center Botany, Dept. of Systematic and Evolutionary Botany, Rennweg 14, Vienna, A-1030, Austria
4 - University of Vienna, Department of Systematic and Evolutionary Botany, Rennweg 14, Vienna, Wien, A-1030, Austria
5 - Royal Botanic Gardens, Kew, Jodrell Laboratory, Richmond, Surrey, TW9 3AB, United Kingdom
Presentation Type: Poster:Posters for Sections
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM