Genetic diversity and population genetic structure of the Wood Turtle (Glyptemys insculpta) at Delaware Water Gap National Recreation Area, USA

Abstract

Glyptemys insculpta is considered to be one of the most endangered freshwater turtles in North America. Here microsatellite markers were employed to investigate the genetic variation and population structure of G. insculpta at Delaware Water Gap National Recreation Area (USA). Seven microsatellites revealed high allelic variation with 13-30 alleles per locus. Observed and expected heterozygosities per locus ranged from 0.875-0.925 to 0.888-0.952, respectively. Pairwise estimates of population structure (h) ranged from 0.000-0.013 to h estimated over all loci and aggregations was not significantly different from zero. Gene flow (Nm) was high and ranged from 19 migrants per generation to infinity in pairwise comparisons. No significant relationship between geographic distance and genetic distance was detected. These data indicate that G. insculpta at DEWA represent a single, genetically diverse management unit for conservation.

Conservation genetics of a peripherally isolated population of the wood turtle (Glyptemys insculpta) in Iowa

“…We sampled G. insculpta from sites 12 km apart along the same drainage in Iowa and along multiple drainages up to 25 km apart in West Virginia and found no hint of population subdivision between sites within a state. This finding is not surprising given that gene flow is evident over greater distances in a large population of G. insculpta from sites 43 km apart along the Delaware River (Castellano et al 2009) and in Québec, except where populations are divided by the St. Lawrence River (Tessier et al 2005).…”

“…More specific locality information will not be reported for this species to minimize poaching (Castellano et al 2009 and references therein). Blood samples were collected via 25-or 27-gauge needle from the left or right brachial vein of the wood turtles.…”

“…Allele size ( compared to a large population of G. insculpta along the Delaware River (Castellano et al 2009), Iowa wood turtles again show lower genetic diversity. For four loci used in both studies, average H E is 0.90 in the Delaware River population and is 0.81 in the Iowa population.…”

“…Tessier et al (2005) found high heterozygosity levels in G. insculpta from Quebec, Canada, despite the population's occurrence at the northern extreme of the species' distribution; the authors suggested that long generation time and gene flow could have preserved genetic diversity in populations that had been in recent decline. Castellano et al (2009) reported similar heterozygosity in a population of G. insculpta that lies along the border of New Jersey and Pennsylvania; the authors suggested that this population has experienced a recent and rapid expansion in population size and that gene flow between multiple aggregations of turtles has helped to maintain its genetic diversity.…”

“…Home range size in G. insculpta appears quite small (Ernst and Lovich 2009;Castellano et al 2009), and many individual turtles display extreme site fidelity (Harding and Bloomer 1979;Arvisais et al 2002Arvisais et al , 2004Tuttle and Carroll 2003;Walde et al 2007). We sampled G. insculpta from sites 12 km apart along the same drainage in Iowa and along multiple drainages up to 25 km apart in West Virginia and found no hint of population subdivision between sites within a state.…”