Whitton, Jeannette , Sears, Chris .
Inferring a better taxonomy for and evolutionary relationships within the North American Crepis agamic complex: evidence from morphology, flow cytometry, cpDNA sequence data, distribution and AFLPs.
The North American Crepis agamic complex consists of nine taxonomic species distributed throughout dry regions of western North America. This superficial taxonomic simplicity masks the effects of polyploidy, apomixis, and interspecific hybridization. The result of these phenomena is innumerable polyploid lineages. Morphologically intermediate polyploids blur the lines between the various diploids, polyploids, and type specimens. All polyploid lineages are thought to have ultimately arisen from diploid populations through auto- and or allopolyploidy. If one is to untie the Gordian knot of polyploid lineages, the diploid populations must first be identified. We have conducted high throughput flow cytometry on field-collected, dried leaf material to characterize DNA ploidy variation within and among populations and species in the North American Crepis agamic complex. A total of 485 samples from 85 populations were analyzed from the regions in which diploids are known to occur. When information gleaned from a detailed analysis of morphological variation, cpDNA sequence data, DNA ploidy, distribution, and AFLPs are synthesized, taxonomic species boundaries and evolutionary relationships are more satisfactorily clarified. Our results illustrate the power of detailed analysis of DNA ploidy variation for clarifying the taxonomy of agamic complexes.
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1 - University of British Columbia, Botany Department, 3529-6270 University Boulevard, Vancouver, British Columbia, V6T 1Z4, Canada
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Cottonwood D/Snowbird Center
Date: Tuesday, July 28th, 2009
Time: 1:45 PM