Biology Colloquium - Dr. Vaughan Symonds

Biology Colloquium - Dr. Vaughan Symonds

Postby cdouglas » Fri Jan 25, 2013 9:03 am


“Dynamics of Polyploid Formation: Recurrent Formation,
Gene Flow, and Population Structure”

Dr. Vaughan Symonds
Senior Lecturer in Plant Genetics
Institute of Fundamental Science
Massey University, New Zealand

Monday, January 28, 2013
3:00-4:00 PM
Science 2, Room 109

Work in my group is essentially split between Population Genetics and Molecular Evolution research. I will be discussing one project in detail that exemplifies our population genetics work and the potential for population genetic approaches and will provide a brief overview of our molecular evolution work. The main focus of the talk will be the origins and evolution of two allopolyploid species in the genus Tragopogon (Asteraceae). Polyploidy (whole genome duplication) is a major feature of angiosperm evolution and diversification. Although most polyploid species have formed multiple times, we know little about the genetic consequences of recurrent formations. Among the clearest examples of recurrent polyploidy are Tragopogon mirus and T. miscellus, each of which has formed repeatedly in the last ∼80 years from known diploid progenitors in western North America. Using progenitor-specific microsatellite markers we examine the genetic contributions to each tetraploid species and assess gene flow among populations of independent formation. These data provide fine-scale resolution of independent origins for both polyploid species. Importantly, multiple origins appear to have resulted in considerable genetic variation within both polyploid species; however, the patterns of variation detected in the polyploids contrast with those observed in extant populations of the diploid progenitors. The results suggest a complicated evolutionary history for both the polyploids and their diploid progenitors that involves multiple introductions, population expansions and extinctions, independent polyploid formations, and variable degrees of gene flow within species.

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