Grady JMSoniat TMRogers JS2010-02-152010-02-151988 198http://hdl.handle.net/1969.3/23084-Allelic variation at 23 presumptive gene loci was assessed among 10 populations of Crassostrea virginica from the northern Gulf of Mexico, extending from Biloxi Bay, Mississippi, westward to Galveston Bay, Texas, using standard procedures of starch gel electrophoresis. Eleven of the 23 loci surveyed proved to be monomorphic across all populations samples. The percentage of polymorphic loci among populations ranged from 0.238 in the Lake Calcalsieu, Louisiana, population to 0.428 in a Terrebonne Bay, Louisiana, sample with a mean of 0.321. Allelic variation at 6 gene loci, Aat-1, Icdh-1, Icdh-2, Mdh-1, Mdh-2, and Sordh, was limited to the occurrence of one or a few rare alleles usually in the heterozyous condition. Allelic diversity was consistently highest among all populations at 6 loci, Gpi, Lap-1, Lap-2, Mpi, Pgdh, and Pgm-1. Allelic distributions at the 12 variable loci were examined for evidence of population subdivision and the presence of potential genetic markers. Estimates of average heterozygosity among populations appeared to be slightly lower than reported for eastern Gulf coastal and Atlantic populations of this speciesallelesASW,Mexico GulfbiopolymorphismCrassostreaCrassostrea virginicaDistributionelectrophoresisGalveston BaygenesGulf of MexicolocimarkersO 8050 CONFERENCESpopulation geneticsPopulationsQ1 01265 Genetics and evolutionQ1 01443 Population geneticsQ1 01583 Shellfish cultureQ3 01583 Shellfish cultureShellfishTexasUSAVariabilityCONF