| Summary: | Inhabiting coastal waters from eastern Canada to the Gulf of Mexico, the eastern oyster is subjected to a wide range of temperature and salinity regimes, thus providing an interesting opportunity to study population structure. Prior studies have examined phenotypic as well as DNA differences along this range. A previous mtDNA population survey of Crassostrea virginica within Pamlico Sound utilizing a single 16s polymorphism diagnostic for North Atlantic / South Atlantic haplotypes revealed an ~110 km cline along the North Carolina coast. Using 4 microsatellite loci, 3 SNPs and 1 scnDNA RFLP, I have surveyed eight oyster populations within and outside the Pamlico Sound in an effort to corroborate the population structure found in the mitochondrial genome. Three microsatellite loci were out of HWE across populations vs. only 1 population for one SNP loci, and it seems likely that those microsatellite loci were plagued with null alleles. Microsatellite exact tests show some significant differences within the Pamlico Sound, mostly in comparisons involving the Stumpy Point population. A combined SNP/RFLP analysis did reveal significant differences among populations, though most of this can be accounted for by inclusion of a population from Maryland. The clinal structure seen in the mitochondrial genome is not reflected in the nuclear genome within the Pamlico Sound.
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