Montgomery, Callie , Shaw, Joey .
Phylogeography of Clematis fremontii S. Wats. (Ranunculaceae) in eastern North America using nrDNA ITS and nDNA G3pdh.
Clematis fremontii S. Wats. (Ranunculaceae) is a diploid perennial forb with strict habitat requirements that occurs in an island-like system of isolated populations in the cedar glades of Missouri and the mixed-grass prairies of Kansas and Nebraska. Based on geographical isolation and morphological differences, this species was formerly subdivided into two varieties, the autonymic prairie variety and the glade variety, C. fremontii var. riehlii Erickson. Interestingly, two disjunct populations of C. fremontii inhabit cedar glades located in Rome, GA and Chattanooga, TN. To illuminate relationships between these four areas of occurrence we are using nrDNA internal transcribed spacer (ITS) and single-copy nuclear gene glyceraldehyde 3-phosphate dehydrogenase (G3pdh) sequence data. Specifically, we hope to gain insight into whether the two eastern populations are recent introductions or disjunct relict populations. Curiously, the cloning process has revealed many rare ITS alleles that were not observed with the initial direct sequencing of PCR products. It appears that incomplete concerted evolution and the presence of ITS pseudogenes are confounding phylogeographic inference; even still, we are currently involved in a large cloning effort to investigate the extent of this phenomenon. To examine the phylogeography of C. fremontii, we are expanding our G3pdh sequence data to include all eastern species of subgenus Viorna displaying erect growth habit and morphology similar to C. fremontii (e.g., C. albicoma Wherry, C. ochroleuca Aiton, and C. viticaulis Steele).
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1 - University of Tennessee Chattanooga, Biological and Environmental Sciences, 215 Holt Hall Dept 2653, 615 McCallie Avenue, Chattanooga, TN, 37403, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Cottonwood B/Snowbird Center
Date: Monday, July 27th, 2009
Time: 4:30 PM