Sex-Associated Mitochondrial Genes: Tools for Understanding Unionid Reproduction and Development

Gonochoristic species of the bivalve order Unionida possess two types of mitochondria. The female-inherited mitochondria (F-mt) is found in the somatic cells of both sexes, while male-inherited mitochondria (M-mt) is found in the male gonad. These mitochondria possess different open reading frames (M-ORF or F-ORF respectively). Previous studies suggested that two types of sperm might exist, each carrying one or the other mitochondrial haplotype, and it was hypothesized that the presence of either F-mt or M-mt in sperm may be involved in determination of offspring sex. I investigated this hypothesis in Bleedingtooth (Venustaconcha pleasii). Sperm samples were obtained from field-collected males that spawned spontaneously in the lab. M-ORF and F-ORF mitochondrial DNA were cloned and sequenced, and PCR was used to test for the presence of M-ORF and F-ORF genes within spermatozoa. F-ORF was not detected within sperm of V. pleasii despite previous reports of the protein product of F-ORF within sperm of V.ellipsiformis. M-ORF was present within sperm and more than one haplotype of this gene appeared to exist within an individual mussel. M-ORF and F-ORF evolve rapidly and may be useful for phylogenetic comparisons. Comparisons with V. ellipsiformis showed 82.6% (M-ORF) and 76.1% (F-ORF) sequence homology. Comparison of F-ORF and M-ORF in V. pleasii display low sequence homology (20.6%). My results indicate that sperm only deliver the M-mt haplotype and therefore, that sex determination must involve mechanisms other than sperm mtDNA haplotype.

Name thesis:degree_name

Master of Science in Biology

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Biology

Year

2015

Author dc:creator

• Maynard, Amy Louise

Contributors dc:contributor

• M. Chris Barnhart

• Unionida
• mussel
• Venustaconcha pleasii
• mitochondria
• sperm
• Biology

Statement dc:rights

• © Amy Louise Maynard

Repository record dc:identifier

https://bearworks.missouristate.edu/theses/974

OAI identifier oai:identifier

oai:bearworks.missouristate.edu:theses-1975