Furches, M. Steven , Wallace, Lisa , Helenurm, Kaius .
Microsatellite variation reveals population structure in the endangered, insular endemic Lithophragma maximum.
LITHOPHRAGMA maximum (Saxifragaceae) is a perennial herb endemic to San Clemente Island, California. Initially discovered in 1936, it is known from only 15 small populations located in moist canyon bottoms along three kilometers of the eastern coastline and has been federally listed as endangered since 1997. Previous allozyme surveys of several of these populations revealed no genetic variation within the taxon. In the present study, genetic variation and differentiation was surveyed using 10 microsatellite loci. Populations vary more than two-fold in P, A, and He, and there is a positive correlation between population size and within-population genetic diversity. Considerable genetic differentiation is evident among populations and canyons; moreover, adjacent populations may be fixed for alternative alleles. Nevertheless, Bayesian analyses performed with the program STRUCTURE suggest that only five or six groups are genetically distinct, indicating some degree of historical connectivity. At least one population shows evidence of a recent reduction of population size consistent with continued pressure from grazing animals.
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1 - University of South Dakota, Department of Biology, 414 East Clark Street, Vermillion, South Dakota, 57069, USA
San Clemente Island.
Presentation Type: Poster:Posters for Topics
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM