Riley, Lynn , McGlaughlin, Mitchell E , Helenurm, Kaius .
Genetic diversity and population structure in Galium endemic to San Clemente Island.
Galium catalinense (Rubiaceae) is a perennial shrub consisting of two subspecies endemic to two of California’s Channel Islands. Galium c. ssp. catalinense is found on Santa Catalina Island, while G. c. ssp. acrispum is a state-endangered taxon that occurs only on San Clemente Island. Populations are small, generally ranging between 1 and 50 individuals, due in part to overgrazing by introduced herbivores and to invasive species. Twelve populations of G. c. acrispum were sampled on San Clemente Island (N=3 to 36) and were surveyed for genetic variation using eight microsatellite loci. In total, 65 alleles were detected in 253 individuals; the number of alleles per locus ranged from 4 to 13. One pair of loci exhibited significant linkage disequilibrium, but only occasional deviations from Hardy-Weinberg equilibrium were detected. Individual populations contain an average of only 3.8 alleles per locus; 10 alleles were unique to single populations. Populations vary about two-fold in the amount of genetic variation they contain: number of alleles per locus ranges from 1.7 to 4.6 and expected heterozygosity ranges from 0.366 to 0.604 (mean He=0.490). Populations fall into three or four genetic clusters. Management strategies based on these genetic data in conjunction with population sizes and the spatial distribution of populations are discussed.
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1 - University of South Dakota, Biology Department, 414 E. Clark Street, Vermillion, SD, 57069, United States
2 - University of Northern Colorado, School of Biology, 501 20th Street, Greeley, CO, 80639, United States
Presentation Type: Poster:Posters for Topics
Location: Event Tent/Cliff Lodge
Date: Tuesday, July 28th, 2009
Time: 5:30 PM