Evaluating the utility of the female-specific mitochondrial f-orf gene for population genetic, phylogeographic and systematic studies in freshwater mussels (Bivalvia: Unionida).

Freshwater mussels (order: Unionida) represent one of the most critically imperilled groups of animals; consequently, there exists a need to establish a variety of molecular markers for population genetics and systematic studies in this group. Recently, two novel mitochondrial protein-coding genes were described in unionoids with doubly uniparental inheritance of mtDNA. These genes are the f-orf in female-transmitted mtDNA and the m-orf in male-transmitted mtDNA. In this study, whole F-type mitochondrial genome sequences of two morphologically similar Lampsilis spp. were compared to identify the most divergent protein-coding regions, including the f-orf gene, and evaluate its utility for population genetic and phylogeographic studies in the subfamily Ambleminae. We also tested whether the f-orf gene is phylogenetically informative at the species level. Our preliminary results indicated that the f-orf gene could represent a viable molecular marker for population- and species-level studies in freshwater mussels.