HAUSWALDT, Susanne/J; GLENN, Travis/C; DRAUD, Matthew/J; University of South Carolina, Columbia and Savannah River Ecology Laboratory, Aiken; Savannah River Ecology Laboratory, Aiken and University of South Carolina, Columbia; Long Island University, Brookville: Population genetics and mating pattern of Diamondback terrapins (Malaclemys terrapin)

The Diamondback terrapin is the only species of turtle in North America that exclusively inhabits brackish waters. Its distribution ranges from Cape Cod to western Texas. Although previous mark-recapture studies indicated that terrapins have high site fidelity to individual tidal creeks or stretches of river over many years, we found very little genetic structure among terrapins within and between different estuaries in South Carolina based on microsatellite allele frequencies using 6 highly polymorphic loci. Genetic differentiation increased only slightly with distance when comparing populations from different states along the East Coast (SC, NC, MD, and NJ). Interestingly, allele frequencies from any of these locations are more similar to those found in terrapins from western Texas than to those from southern Florida. We also sequenced the entire mitochondrial control region in terrapins from the same locations. Apart from a highly polymorphic microsatellite on the 12S side and a ~100 bp fragment on the cytB side of the control region that is repeated up to 5 times, we found only 7 polymorphic and parsimony informative sites among 27 individuals. We used the microsatellite in the control region to examine the frequency of heteroplasmy among 120 terrapins. Over half of the individuals had more than one allele, and at most we found 4 different alleles for this locus. We are currently genotyping 40 mother/clutch samples from Long Island, NY to investigate occurrence of multiple paternity.