LE3 .A278 2014

2014

Stewart, Don

Acadia University

Bachelor of Science

Honours

Biology

Biology

Mytilus edulis, Atlantic blue mussels, demonstrate doubly uniparental inheritance (DUI) of mitochondrial (mt) DNA. Females are homoplasmic for a female-transmitted mtDNA genome (the F-type), and males are heteroplasmic for an F-type and a male-transmitted genome (the M-type). F-types can undergo “role reversal” events, resulting in a new M-type known as a recently masculinized (RM) type that co-occurs in the population with the evolutionarily older standard male (SM) type. Previous studies demonstrated that sperm with RM mtDNA have increased velocity in comparison to sperm with SM mtDNA. It was hypothesized that faster sperm containing RM mtDNA would have a selective advantage in dense populations, whereas slower but presumably longer lived sperm containing SM mtDNA would be selected for in sparse populations. This study examined nine populations of M. edulis to document the geographic distribution of mtDNA polymorphisms in male mussels along the coast of Western Nova Scotia. A variety of molecular techniques, including the polymerase chain reaction, restriction enzyme digests and Sanger sequencing were used to determine species and mitotype. The RM mitotype was found in five populations along the western coast of Nova Scotia, including two populations on the Fundy shore. RM mitotypes were in greatest proportions at two densely populated sites, however, the difference in the proportion of the RM type among sites was not statistically significant. The SM type was, however, the most common type in all populations, which suggests that there may be other selective pressures acting on mitotype distribution. Further analysis on M. edulis populations is required to better characterize the various selective pressures affecting the geographic distribution of RM and SM mitotypes in M. edulis.

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https://scholar.acadiau.ca/islandora/object/theses:1102