Somatic Mutations in Mitochondrial DNA of Drosophila
Authors: Mara Baylis; Jakob McBroome; Russell Corbett-Detig
Affiliation: University of California, Santa Cruz
Keywords: Comparative genomics & genome evolution
In humans, increasing heteroplasmy -or genetic variation of mitochondrial DNA within the body- has been associated with aging, neurodegenerative disease, cancer, and muscle degeneration disorders. However, the occurrence and distribution of the mitochondrial somatic mutations that create heteroplasmy remain poorly understood. Evaluating how these mutations accumulate through the lifespan of an organism and what genetic mechanics create them is key to understanding the aging process at a fundamental level. Using an ultra-accurate sequencing technique capable of detecting low-frequency variation within a single tissue sample, I have identified very low-frequency mutations at high accuracy in Drosophila mitochondrial DNA. To address this question, we are using Drosophila melanogaster as a model organism, as they are well suited to this research. By analyzing multiple individuals across different life stages, I compared mitochondrial mutational loads and evaluate the accumulation of heteroplasmy across the Drosophila lifespan. This life stage data will also be used to determine the different types of mutations occurring, can be used to draw conclusions about the presence of a selection event that occurs within the life stages, which could indicate that somatic selection occurs after the bottleneck in oogenesis. Additionally, I have identified conserved regions in mtDNA, evaluated mitochondrial diversity within and between cells, and revealed patterns related to underlying mechanisms of mutation.