LE3 .A278 2018

2018

Stewart, Don

Acadia University

Bachelor of Science

Honours

Biology

Biology

Freshwater mussels, or unionids, are declining at a catastrophic rate. As keystone species, they make up as much as 95% of the benthic biomass, and their decline could radically alter benthic ecosystems. Here the use of the rapidly mutating, novel open reading frame on the female-type mitochondrial genomes (f-orf) of these unionids is investigated in comparison to the cytochrome c oxidase subunit 1 gene (cox1) as a means to differentiate between closely related freshwater mussel species and to detect evidence of hermaphroditism. The eastern floater, Pyganodon cataracta (Say, 1817) and the Newfoundland floater, P. fragilis (Lamarck, 1819), are two putative freshwater mussel species. Previous morphological and molecular attempts at differentiating them have indicated they are the same species. Species-specific primers were designed, and target f-orf sequences were PCR amplified and sequenced via Sanger sequencing. Phylogenetic analysis of both F f-orf and previously sequenced cox1 sequences indicated the samples were of the same species, and no identifiable evolutionary significant units (ESUs) and/or management units (MUs) were observed. There was not any evidence of hermaphroditism based on these f-orf sequences. These f-orf sequences may still be useful in other species of unionids to distinguish among closely related species, to assign conservation status in imperilled mussel taxa to help identify and protect populations that are genetically distinct, and to maximize adaptive potential of unionids species as a whole, or to detect evidence of selection for hermaphroditism as a reproductive strategy.

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https://scholar.acadiau.ca/islandora/object/theses:2689