Shaw, Joey , Binkley, Meagan .
Phylogeography of North American Chestnuts and Chinquapins (Castanea Mill., Fagaceae).
North American Castanea Mill. (Fagaceae) consists of three morphologically variable species: Castanea dentata, Castanea pumila and Castanea ozarkensis. Taxonomy of these species has been complicated by intermediate morphology, similarity in growth habit, and putative naturally occurring hybridization where speciesí ranges overlap in the southern Appalachians. The goals of the present study were to determine if genetics reflect the morphological variation observed in southeastern populations of North American Castanea, explore the extent of cpDNA haplotype sharing among these taxa, and map haplotype distributions. Finally, we wanted to use the information to gain insight into southeastern populations, where intermediate morphologies and putative hybridization are confounding taxonomy. To that end, we sequenced the cpDNA trnV-ndhC intergenic spacer region for 233 accessions collected throughout the range of the genus, with a focus on southern Appalachians. We identified four main chloroplast haplotypes and observed that for three of these haplotypes, leaf morphology is a reliable indicator of haplotype identity. The fourth haplotype is shared among accessions of C. dentata and C. pumila, and is also found in trees with intermediate morphology. The geographic mapping of these haplotypes revealed that each haplotype is found in a separate geographic range, allowing for the comparison of current distributions with locations of possible glacial refugia.
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1 - University of Tennessee, Chattanooga, Department of Biological and Environmental Sciences, 215 Holt Hall, Department 2653, 615 McCallie Avenue, Chattanooga, Tennessee, 37403, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Cottonwood B/Snowbird Center
Date: Monday, July 27th, 2009
Time: 5:00 PM