Systematics Section / ASPT
Ellis, Mark W. , Gainer, Rochelle E. , Wolf, Paul G. .
Genetic analyses support taxonomic recognition of Eriogonum corymbosum var. nilesii.
THE shrubby buckwheat species Eriogonum corymbosum is widely distributed in the western US and shows broad morphological and ecological variation over its geographic range. The complex of E. corymbosum varieties presents taxonomic challenges as a result of a putative history of dispersion, isolation, divergence, and hybridization. A relatively disjunct group of E. corymbosum populations found in Clark County, Nevada, has historically been identified as variety glutinosum, which is also found in southern Utah and Northern Arizona. The apparently distinctive combination of morphological characters and ecological conditions is the basis for a recent revision that designates the group of populations in Clark County, Nevada, as E. corymbosum var. nilesii. Our objective is to examine and compare the genetic variability within and among E. corymbosum var. nilesii with that of similar populations in the west, particularly Utah and Arizona. We have examined 419 individuals from 51 Eriogonum populations to compare genetic variation within the E. corymbosum complex and among related species. Using Amplified Fragment Length Polymorphisms (AFLPs) we generated 95 polymorphic markers, and analyzed the AFLP profiles with principle components and UPGMA cluster analyses. These analyses show clear separation of E. corymbosum var. nilesii populations in Las Vegas Valley from all other populations. We also sequenced the trnH-psbA chloroplast spacer region for 92 individuals from 38 populations. We observed 29 nucleotide substitutions and 34 nucleotide insertion/deletions for a total of 63 unique sequence characters and 17 haplotypes. Fifteen of the 16 E. corymbosum var. nilesii samples had the same unique haplotype. The results of AFLP analyses and sequencing show a level of genetic divergence that supports the taxonomic recognition of variety nilesii for the Nevada populations.
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1 - Utah State University, Department of Biology, College of Science, 5305 Old Main Hill, Logan, Utah, 84322, USA
Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM