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Abstract Detail


Polyploidy: Genetics, Evolution and Ecology

Whitton, Jeannette [1].

Insights into polyploid evolution from the study of agamic complexes: multiple origins and patterns of geographic parthenogenesis.

Agamic complexes are polyploid complexes in which some or all polyploids reproduce predominantly asexually, through the production of apomictic seeds. Diploids in these groups are nearly always sexually reproducing. Two agamic complexes in the sunflower are used to illustrate some of the insights into polyploid evolution that can be gleaned from the study of agamic complexes. In the North American Crepis, analysis of ploidy, morphological and molecular variation of populations of the nine taxa help to clarify the origins and spread of variation in this group. Studies of contact zones reveal that multiple origins of polyploid apomicts can establish lineages capable of coexistence on local scales. In contrast to sexual polyploids which are likely to exchange genes across populations of the shared ploidy, apomictic polyploids in Crepis exhibit strong barriers to gene flow as a result of asexuality. In Townsendia, a system in which asexual lineages appear to be autopolyploids, ecological differences between diploids and polyploids, as well as multiple origins allows for testing the impact of distinct origins on ecological tolerances. Insights into polyploid evolution from these and other agamic complexes provide a complement to studies of sexual polyploids.


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1 - University of British Columbia, Department of Botany, Vancouver, BC, V6T 1Z4, Canada

Keywords:
apomixis
polyploidy
Asteraceae.

Presentation Type: Symposium or Colloquium Presentation
Session: S8
Location: Room 2/Woodward
Date: Tuesday, July 29th, 2008
Time: 1:30 PM
Number: S8002
Abstract ID:894


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