Roberts, Roland , Naylor, Helen , Nicholson, Eric , Miller , Bailey .
Chrysothamnus revisited: The quest for phylogenetic resolution among rabbitbrush and its relatives using multiple nuclear and chloroplast genes.
The genus Chrysothamnus (rabbitbrush), is a widespread group which, along with Artemisia, dominates the sagebrush ecosystem of the southwestern United States. Its distribution, however, also extends into Mexico and Canada. Chrysothamnus is classified within tribe Astereae and subtribe Solidagininae. The monophyly of several genera within subtribe Solidagininae and their relationship to one another was investigated using nuclear ribosomal DNA (nrDNA; ITS and ETS). Those analyses revealed that Chrysothamnus, as then defined, was not monophyletic. Also, assessment of monophyly of several genera related to Chrysothamnus was equivocal. Furthermore, the nrDNA failed to fully resolve relationships among species both within Chrysothamnus and related genera. Here we expand sampling, to include duplicate taxa, from within the known range of sampled genera. This sampling strategy aided our initial assessment of genetic variation across the range of each taxon sampled. In addition, we collected and analyzed data from several chloroplast regions. Independent analyses of the chloroplast data revealed the potential for resolving both ancient and recent evolutionary history within the Solidagininae. Combined analysis with the nrDNA data revealed stronger support for some of the major lineages and greater resolution of evolutionary relationships among infrageneric taxa.
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1 - Towson University, Department of Biological Sciences, 341 Smith Hall, Towson, Maryland, 21252, USA
2 - Towson University, Biological Sciences, 8000 York Road, Towson, Maryland, 21252, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Cottonwood D/Snowbird Center
Date: Wednesday, July 29th, 2009
Time: 11:15 AM