Genetics / Functional Genomics / High Frequency / Phylogeny / Mitochondrial DNA / Bivalvia / Genetic Structure / Female / Animals / Male / Gene / Mitochondrial Genome / nuclear DNA / North America / North American / Base Sequence / Divergence Time / Bivalvia / Genetic Structure / Female / Animals / Male / Gene / Mitochondrial Genome / nuclear DNA / North America / North American / Base Sequence / Divergence Time