Waselkov, Katherine , Olsen, Kenneth , Schaal, Barbara .
Molecular phylogenetics and weed evolution in the genus Amaranthus (Amaranthaceae).
The genus Amaranthus (Amaranthaceae; Caryophyllales) is widespread in warm temperate and tropical regions of the world; the majority of species are native to the Americas, but the group also includes species native to Eurasia, South Africa, and Australia. The genus is infamous for its cosmopolitan weed species associated with anthropogenic habitats, but many Amaranthus species are restricted to naturally disturbed habitats, and the genus even includes some island endemics. We are endeavoring to reconstruct the phylogeny of Amaranthus molecularly, using two chloroplast and three nuclear genetic regions, in order to explore the evolutionary association of morphological and ecological characters with "weediness," which we define as the tendency to invade agricultural ecosystems. Our sampling includes 62 species, from all the major geographical regions where Amaranthus is native, and we have reconstructed phylogenetic trees using MP, ML, and Bayesian methods to analyze sequence data from the matK, trnC-D, ITS, G3PDH, and A36 genetic regions (separately and concatenated). Preliminary results show that mating system (dioecy vs. monoecy) is homoplasious in the genus, as is "weediness," which has evolved several times facilitated by different suites of morphological and ecological characters.
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1 - Washington University In St. Louis, 1 Brookings Drive, Campus Box 1137, Saint Louis, MO, 63130, USA
2 - Washington University, BIOLOGY DEPT, BOX 1137, 1 BROOKINGS DRIVE, St. Louis, MO, 63130-4899, USA
3 - Washington University, Department Of Biology, CAMPUS BOX 1137, 1 Brookings Drive, St. Louis, MO, 63130-4899, USA
morphological character evolution.
Presentation Type: Oral Paper:Papers for Sections
Location: Delaware C/Hyatt
Date: Wednesday, July 11th, 2012
Time: 2:15 PM