Molecular Ecology and Evolution
Symonds, V. Vaughan , Soltis, Douglas E. , Soltis, Pamela S. .
Microsatellite markers reveal a genetic sieve to the multiple origins of Tragopogon allopolyploids.
Polyploidy is widely recognized as a major force in plant evolution. While it is clear that most polyploid species form recurrently, the factors that regulate polyploid formation and the genetic consequences of multiple origins remain largely unknown. To address these issues we studied the genetic composition of two recently evolved allopolyploid species, Tragopogon miscellus and T. mirus (Asteraceae). These two species evolved following the introduction of three diploid Tragopogon species to the Palouse region of the northwestern US. One of the diploids, T. dubius, is a progenitor for both polyploid species and T. pratensis and T. porrifolius served as the other parents for T. miscellus and T. mirus, respectively. A total of 20 microsatellite loci was used to assess (1) the number of origins for each polyploid species, (2) gene flow among independent polyploid formations, and (3) the distribution of genetic diversity within and among populations of both polyploids and their progenitors. Our data suggest that every polyploid population represents at least one novel origin and gene flow among populations, though at a very low rate, does occur. Perhaps the most significant finding is that relatively few combinations of progenitor alleles are observed in the polyploid species. This finding may reflect either historical population structure of the progenitors, a genetic barrier to either inter-specific hybridization or polyploid formation, or some combination of these.
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1 - Massey University, Institute of Molecular BioSciences, Private Bag 11222, Palmerston North, New Zealand
2 - University of Florida, Department of Botany, 220 Bartram Hall, P.O. Box 118526, Gainesville, Florida, 32611-8526, USA
3 - University of Florida, Florida Museum of Natural History, PO Box 117800, Gainesville, FL, 32611-7800, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Boulevard B/Hilton
Date: Wednesday, July 11th, 2007
Time: 10:45 AM