Molecular Ecology and Evolution
Servick, Stein , Soltis, Pamela S. , Soltis, Douglas E. .
Microsatellite Evidence for Polyploid and Cytotype Origins in Galax urceolata¬†(Diapensiaceae).
Polyploidy has long been recognized as a significant force in the evolution of plants. Genomic studies indicate there have been multiple whole-genome duplications throughout the evolutionary history of angiosperms, indicating the importance of polyploidy in angiosperm diversification. However, most research has focused on allopolyploidy and synthetic autopolyploids, leaving naturally occurring autopolyploids generally underinvestigated. Recent studies indicate that the prevalence of autopolyploid speciation has been largely underestimated. To improve our understanding of the role of polyploidy in evolution, studies on naturally occurring autopolyploids are therefore essential. We seek to broaden our understanding of autopolyploidy as an evolutionary force in natural populations through investigation of the genetic consequences of whole-genome duplication in Galax urceolata (Diapensiaceae), long considered the classic example of autopolyploidy. Galax urceolata comprises 2x, 3x, and 4x cytotypes (n = 6) that are morphologically and chemically nearly identical, suggesting an autopolyploid origin. We developed microsatellite markers and have preliminarily screened 800 individuals from 55 populations to determine whether G. urceolata meets the theoretical genetic expectations of an autotetraploid (e.g., nearly all alleles shared with the putative diploid progenitor(s), genotypes containing 1-4 alleles per locus, and tetrasomic inheritance). Bayesian models have been employed to determine the likelihood of disomic vs. tetrasomic inheritance and to infer whether the tetraploid is of auto- or allopolyploid origin. Microsatellite data have also been utilized to determine whether there was a single origin of the tetraploid cytotype or multiple independent origins.
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1 - University of Florida, Department of Biology, Florida Museum of Natural History, P.O. Box 117800, Gainesville, FL, 32611-7800, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Maybird/Cliff Lodge - Level C
Date: Tuesday, July 28th, 2009
Time: 8:45 AM