HAYES, B.M.*; ERICKSON, J.M.; TEMKIN, M.H.; St. Lawrence University; St. Lawrence University; St. Lawrence University: A Nested Cladistic Analysis of the Geographical Distribution of Mitochondrial DNA Haplotypes of the Freshwater Mussel Elliptio complanata from Northern New York

Freshwater mussels in northern New York inhabit eight major rivers (Indian, Oswegatchie, Grass, Raquette, St. Regis, Salmon, Great Chazy-Saranac and Ausable) and several minor ones that drain the Adirondack Highland as north-flowing tributaries to the St. Lawrence River. The geographical distribution of genetic variation among populations of freshwater mussels in northern New York may be structured by levels of gene flow within and among rivers through the dispersal of glochida larvae attached to fish gills and/or historical events (e.g., fragmentation and range expansion). The ancestral stocks of the current freshwater mussel fauna immigrated into the region about 10,000 years ago, following the regression of the Labrador ice sheet. A complicated series of postglacial drainage connections allowed freshwater mussels to enter the river systems of northern New York from areas east and south of the glacial border and from portions of the Ohio and Mississippi river basins south of the glacial border. Postglacial intra-basin geomorphic history has caused adjacent rivers to exchanged portions of their drainages through stream capture. In an initial attempt to evaluate the significance of gene flow and population history on the geographical distribution of genetic variation in freshwater mussels of northern New York, we used a nested cladistic analysis of mitochondrial haplotypes of Elliptio complanata, based on the PCR amplified sequences of the cytochrome C oxidase subunit I (358 bp) and 16s rRNA (320 bp) genes. Inferences based on this analysis suggest that both restricted gene flow and past fragmentation events have influenced the geographical distribution of E. complanata haplotypes in northern New York.