Systematics Section / ASPT
Hertweck, Kate L. , Pires, J. Chris .
Population dynamics of polyploidy: Phylogenetics, cytogenetics, and hybridization of Tradescantia (Commelinaceae).
CURRENT work on evolution of polyploidy focuses primarily on cultivated plants and is restricted to a few taxonomic groups (e.g., Triticum, Gossypium, Brassica, and Nicotiana). With the exception of notable groups like Tragopogon, Rosa, Spartina, and Chamerion, few researchers have investigated the dynamics of polyploidy and hybridization in natural plant populations. The genus Tradescantia (Commelinaceae) is often studied cytologically, but also provides an interesting system in which to study natural populations with hybridization and polyploidization. Most North American Tradescantia are endemic to specific localities, although some are widespread or tropical. According to work done by Edgar Anderson in the early twentieth century, Tradescantia is known to hybridize frequently and exhibits interesting chromosomal changes (e.g., rearrangements and aneuploidy). We are employing number of modern approaches, including phylogenetics, cytogenetics, and greenhouse studies, to examine the evolution and population dynamics of natural polyploids. A molecular phylogeny of Tradescantia and other New World Commelinaceae using both chloroplast (e.g., rpl16) and low copy nuclear genes (e. g., PHYC) is being employed to evaluate the monophyly of subtribe Tradescantiinae. These relationships will be compared with ploidy levels to determine the evolution of chromosome number in this portion of Commelinaceae. A smaller group of Ozark Tradescantia is being examined for genetic diversity and spatial patterns of hybridization using a phylogeographic approach. Molecular cytogenetic markers are being isolated to identify chromosomal changes in native Ozark Tradescantia following hybridization and/or polyploidization. Finally, the ploidy levels of natural hybrids can be compared to synthetic hybrids raised in the greenhouse to determine if hybrids of all potential ploidy levels are able to survive in nature. This research helps elucidate patterns of formation, establishment, and evolution of hybrids and polyploids in a natural setting, and provides a starting point for other ecological and evolutionary studies in Commelinaceae.
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1 - University of Missouri Columbia, Biological Sciences, 1201 Rollins Road, Life Sciences Center 311, Columbia, Missouri, 65211, USA
Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM