Jordon-Thaden, Ingrid , Koch, Marcus .
Phylogeography, Phylogeny and Speciation in the Global Genus Draba, (Brassicaceae).
This presentation summarizes our current work on the phylogeography and phylogeny of the largest genus in the Brassicaceae, Draba. There over 370 Draba species and they are distributed globally in extreme ecosystems such as high altitude and latitude. It is an excellent model for studying the global migration of species in alpine/acidic habitats which are occurring in currently or historically relatively continuous paths of major mountain areas and polar regions. Genetic diversity data analyzed in a framework of phylogeography (using gene trees) and phylogeny (using species trees) are correlated in this study. These analyses are essential keys to understanding the formation of species, which is still a central focus of modern evolutionary research. We are exploring under what types of circumstances a species develops or why some genera appear to be more species-rich compared to others. By understanding the natural history of an entire global genus and incorporating geological events such as glaciation cycles, we are able to hypothesize about what possible ecological factors have led and lead to further speciation. The natural history of the genus Draba can be understood by identifying the center of origin, its migration routes, current and past habitat structure, calculating speciation rates and measuring genetic mutation rates. In addition, a long-standing hypothesis about the origin of a genus is that the location of highest diversity, both in numbers of species in an area and in the corresponding genetic diversity, is also the same as its origin. In the case of Draba, we are proposing that the area of highest genetic diversity is correlated with the region of origin, but not necessarily the area of highest species (alpha) diversity. Only in a phylogeographic context can such questions be explored.
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1 - Institute of Plant Sciences Hip, Biodiversity And Plant Syst., Im Neuenheimer Feld 345, Heidelberg, D-69120, Germany
Presentation Type: Oral Paper:Papers for Topics
Location: Cottonwood B/Snowbird Center
Date: Monday, July 27th, 2009
Time: 2:15 PM