Molecular Ecology and Evolution
Enke, Neela , Gemeinholzer, Birgit .
Karyotype Evolution and Speciation in Higher Plants: The Genus Crepis L. (Cichorieae, Compositae).
The genus Crepis L. with over 200 species is widely distributed throughout the northern hemisphere and Africa. In the last revision of the genus (Babcock, 1947) the species were assigned to 27 sections mainly based on karyotypic characteristics especially chromosome numbers. The basic chromosome number varies considerably (x=3-6, 11) within the genus and even between closely related species. Current karyological studies suggest that structural karyotype characteristics and similarities in chromosome morphology are more indicative of phylogenetic relationships in Crepis L. than chromosome number alone.
Following Babcock’s (1947) hypotheses it was mainly a change in chromosome number which led to interspecific sterility and speciation, while hybridisation only played a minor role in the development of new species. However, recent phylogenetic studies on Crepis L. revealed a far more complex pattern of karyotype evolution than Babcock (1947) assumed. Furthermore, comparison of nuclear and chloroplast marker very strongly hint to multiple hybridisation events during evolution of the genus which resulted in further karyotype developments.
As most members of the genus are diploid and non-apomictic, Crepis L. could be a model group to understand complex mechanisms of karyotype evolution resulting in speciation.
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1 - Botanic Garden and Botanical Museum Berlin-Dahlem, Freie Universitaet, Labors, Koenigin-Luise-Str. 6-8, Berlin, 14195, Germany
2 - Botanic Garden and Botanical Museum Berlin-Dahlem, Free University Berlin, Koenigin-Luise-Straße 6-8, Berlin, 14195, Germany
Presentation Type: Oral Paper:Papers for Topics
Date: Tuesday, July 29th, 2008
Time: 1:30 PM