Characterization of Genic Microsatellite Markers (EST-SSRs) in the Endangered Tree Quercus georgiana. PRIYANKA KADAV1, MURPHY WESTWOOD2, ANDREA KRAMER3, JEREMIE FANT3, ANDREW HIPP2, RAAKEL TOPPILA2, SEAN HOBAN2, OLIVER GAILING1, 1Michigan Technological University, 2The Morton Arboretum, 3 Chicago Botanic Garden
Quercus georgiana is an endangered endemic oak species that exists only in a few scattered populations in the southeastern US. The aim of the project is to characterize genic microsatellite markers (EST-SSRs) in this endangered tree species in four populations from Georgia. A total of 27 EST-SSRs have been tested for locus-specific amplification in eight Q. georgiana samples from the four different populations, out of which 12 have been selected based on the amplification of a single polymorphic gene locus for the analysis of all 300 samples. Samples were amplified in a GeneAmp PCR system 2700 using the EST-SSRs. PCR amplicons were separated on an ABI 3730 Genetic Analyzer with the internal size standard GS-LIZ-500 and scored with GeneMarker V.2. 6.7. An initial assessment of the genetic variation parameters expected heterozygosity (He), observed heterozygosity (He) and number of alleles per locus (Na) was done in GENAlEx6 using EST-SSRs. In addition, the inbreeding coefficient F was calculated for each marker in GENAlEx. Observed heterozygosity (Ho) and expected heterozygosity (He) for individual markers ranged from 0.273 to 1.000 and from 0.247 to 0.867, respectively. The number of alleles per locus (Na) ranged from 2 to 11. Genetic differentiation among populations (FST=0.067) was comparatively high with pairwise FST values ranging from 0.024 to 0.119. The mean genetic variation for the four populations fragments was 0.677 (Ho) and 0.655 (He). High genetic differentiation between neighboring populations could indicate genetic drift.