Eric Swenson and Dr. Keith Crandall, Zoology

DNA sequence analysis can be a very powerful tool to examine the evolutionary history of many different species of organisms. One of the most useful benefits is determining species lineage and evolutionary relationships. In this study we attempted to examine the phylogenetic relationship of Eurycea bislineata, an east coast salamander by examining the Cytochrome b, and ND4 gene regions of the mitochondrial DNA genome.

The two-lined salamander Eurycea bislineata (Green 1818) has a wide geographic range. The range extends from southeastern Canada in the north to northern Florida in the south, and as far west as the Mississippi River, extending to the Atlantic Ocean (Petranka). Within this larger distribution there is extensive morphological variation among three different sub-species which are: E. b. bislineata (Green 1818) which is the northern most located sub-species with its range extending from southeastern Canada as far south as northern Virginia and extending partially into eastern Ohio. E. b. cirrigera (Green 1831) extends from northern Virginia south to the gulf coast reaching as far west as Mississippi and eastern Illinois. E. b. wilderae (Dunn 1920) has the smallest geographic range which is confined to the southern Appalachian mountains, mostly within eastern North Carolina. Within E. b. wilderae Sever, (1979) described a morph calling it “Morph A” which had slight differences from E. b. wilderae. All species occur in a variety of habitats ranging from sea level up to 2000 meters in elevation (Petranka). Individuals can be found in moist areas on forest floors such as under logs or rocks, close to seeps and in fresh water streams (Petranka).

In the past distinctions among all the sub-species was made only on morphological variation. However the differences are subtle and leave much room for debate and inconsistencies. Other molecular studies have been performed, but have utilized poor geographic sampling methods by not sampling from the contact zones of the different sub-species. In this study we had a more comprehensive sampling method, with emphasis on the contact zones.

This project is still being completed due to complications obtaining DNA sequences for all of the samples in the ND4 gene region. Because there was variation in the priming region of the ND4 gene, internal primers had to be developed and optimized in order to complete the data set. The data set of all gene sequences is very near completion. Once completed, the DNA sequences will be analyzed using the computer program PAUP to draw conclusions about the phylogenetic relationships among the different taxa examined.

Preliminary analyses have not been able to draw any definite conclusions about what the status of the salamanders should be. Latitude and longitude coordinates may be used to help draw more definite geographic locations, so that this information can be incorporated into the topology of the phylogenetic tree and make more definite conclusions. I am confident that the finished project will give great insight into the relationship of these salamanders that are as of now with out distinction.