Research Training Program

Stephanie Schroeder
University of Wisconsin--Milwaukee
Milwaukee, WI

Jerry Harasewych, Ph.D
Supervising Scientist
Department of Invertebrate Zoology

"In a matter of ten weeks I went from a mild understanding of molecular systematics to living and breathing it."

The biogeography of many species has been thought to be affected by Florida acting as a genetic barrier. By examining the subgenus Sinistrofulgur, snails which coil to the left, we speculate that these species can be added to the list of species affected by Florida. The left coiling snails have been present along the Eastern coast of North America since the Pliocene period approximately 2 million years ago, but it is not known whether the mutation is monophyletic, that is, resulting from one giant event or a result of different ancestral mutations. It is speculated that the mutation arose from one dynamic mutation. When Random Amplified Polymorphic DNA (RAPD) Polymerase Chain Reaction (PCR) techniques were applied to the subgenus, it was discovered that Florida does in fact, pose as a barrier for various Sinistrofulgur species. PCR allows us to take DNA and amplify it hundreds or thousands of times a second, resulting in a plethora of DNA to examine. By running the amplified DNA on a gel we can compare the bands created and determine the similarities between the species. The combination of molecular techniques and systematics allows for a greater understanding and differentiation of closely related species and through RAPD PCR, we also discovered a left coiling snail of the genus Busycon (the genus the Sinistrofulgur belongs to) that was actually a mutation of a right coiling snail.