TAXONOMIC IDENTIFICATION OF FRESHWATER MUSSELS OF THE ST. CROIX RIVER THROUGH DNA ANALYSIS.

Megan Albert, Cynthia Harrison, James G. Straka, Mark Hove and Daniel Hornbach. Departments of Biology and Chemistry, Macalester College, St. Paul, MN 55105.

Freshwater mussels are an important component of freshwater ecosystems, storing energy that otherwise would be lost downstream, while serving as good ecological indicators and food sources for other organisms. They are a highly diverse family of organisms that are rapidly declining in species richness and abundance. Mussels undergo a period of parasitic encystment on fish hosts during the larval (glochidial) stage of their life cycle. A better understanding of host- parasite relationships would be highly beneficial to mussel conservation; however, mussels in the glochidial stage are very small and therefore extremely difficult to identify. In this project, we use the polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) techniques on the ITS-1 region of the mussel genome in an attempt to identify genetic markers for each species. To do this, genomic DNA is extracted from adult mussel specimens, the ITS-1 region is amplified using PCR and the amplified DNA digested with a selected array of restriction enzymes. Our goal is to create an identification key based on these genetic markers for all the mussel species of the St. Croix River. The resulting taxonomic key may be used to unambiguously identify mussels while in their glochidial forms. To date, DNA patterns have been recorded for 22 mussel species. Currently, we are working on expanding this database, and refining our protocols to make identification more accurate and efficient. Our data thus far suggests that the mussel species of the St. Croix River can indeed be distinguished using this technique, and that these methods may serve as a valuable tool for mussel conservationists.

Key words: genetic markers, unionid, Saint Croix River

Presenting author: Mark Hove, Macalester College, 1600 Grand Ave., St. Paul, MN 55105. Phone (651) 696-6827 FAX (651) 696-6443 e-mail Mark.Hove@fw.umn.edu