Systematics/Phytogeography / Taxonomie/ Section
Pleines, Thekla , Blattner, Frank R. .
AFLPs resolve phylogenetic relationships in a narrow group of diploid New World Hordeum species (Poaceae).
The genus Hordeum (Poaceae, Triticeae) originated about 12 million years ago in southwestern Asia. The New World was colonized about 5 million years ago via Beringia. In southern South America a rapid and recent radiation took place during the last 2 million years. To analyze diversification processes in this South American group, a good hypothesis of species relationships is necessary. Phylogenies based on chloroplast data are problematic in this group, because of widespread incomplete lineage sorting of chloroplast alleles. Nuclear genes exhibit only a low number of polymorphisms due to the young age of the group. Here we used AFLPs (amplified fragment length polymorphisms) to resolve the species relationships within the New World clade. Two samples of diploid Asian Hordeum species were included as outgroup taxa. The AFLP analysis was able to resolve species relationships, showing Californian H. brachyantherum as sister species to four major phylogenetic groups from South America. Within these latter groups, sister species can be resolved with high bootstrap support, while statistical support for branches defining the relationships among these groups is low. The AFLP results support the monophyly of the only three annual New World species, as well as earlier findings regarding intercontinental long-distance dispersals from North to South America and vice versa.
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1 - Institute of Plant Genetics and Crop Research (IPK), Taxonomy & Evol. Biology, Gatersleben, D-06466, Germany
Presentation Type: Poster:Posters for Sections
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM