Bryological and Lichenological Section/ABLS
Leavitt, Steven D. , Porter, Lindon , St. Clair, Larry L. .
Genetic Variation and Population Structure in the Lichen-forming Ascomycetes Rhizoplaca melanophthalma and Rhizoplaca chrysoleuca in Western North America.
The umbilicate lichen species Rhizoplaca chrysoleuca and Rhizoplaca melanophthalma are widespread, both geographically and ecologically. Within both species, morphological and molecular divergence has been identified. However, ecological and geographic distribution of this diversity has not been tested. In this study, morphological, chemical, and genetic diversity are investigated along an altitudinal gradient on two mountains 20 km apart in east central Utah, USA, Thousand Lake and Boulder mountains. Both species exhibit significant molecular and morphological variation and multiple well-supported clades are inferred from phylogenetic analyses within each species. Pairwise comparisons of sampled populations (FST, exact tests of population differentiation) reveal significant differentiation between populations in different habitats and also between some expressed secondary metabolites. However, general population structure within the most wide-spread clades is not identified between populations in different altitudinal zones. Individuals in well-supported clades in both species showed a significant number of fixed loci, indicating no gene flow between members from different clades. Potential novel species within these genetically diverse taxa will be empirically tested using population aggregation analysis and Templetonís test of cohesion. The well-supported R. melanopthalma assemblege also includes representatives of R. cerebriformis and R. subidahoensis, suggesting either a broader circumspection of R. melanophthalma to include these species or additional subdivision within the species.
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1 - Brigham Young University, Department of Biology and M.L. Life Science Museum , 401 WIDB Brigham Young University , Provo, Utah, 84602, USA
2 - usda-ars, Vegetable and Forage Crops Research Unit, 24106 North Bunn Road, Prosser, Washington, 99350, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Magpie B/Cliff Lodge - Level B
Date: Monday, July 27th, 2009
Time: 11:45 AM