Abstract Mitochondrial dysfunction results in disorders that affect one in 4,000 people, and diseases associated with aging, such as neurodegeneration and cancer. Improper function of a mitochondrial quality control process, mitophagy, as well as mutations in mitochondrial DNA (mtDNA) are implicated in these diseases. The role of environmental pollutants and mitophagy in the origin and transmission of mtDNA mutations is poorly understood. The objective of this proposal is to investigate variation in susceptibility to chemical-induced mtDNA damage in the context of mitochondrial homeostatic processes, how DNA damage can lead to mtDNA mutations, and the functional consequences of these mutations. The model organism Caenorhabditis elegans has a highly conserved mitochondrial genome and well characterized mitochondrial biology, and provides an extremely tractable genetic and toxicological model for this research proposal. We hypothesize that C. elegans that are genetically deficient in mitophagy will accumulate and retain higher levels of mtDNA damage compared to wild type after exposure to the environmental toxicants and known mutagens, cadmium and Aflatoxin B1. We propose that this will increase mtDNA mutation frequencies. This work will also inform the role of mitophagy in transmission of mtDNA mutations into the next generation. To detect rare mtDNA mutations, we will adapt a well- established and highly-sensitive sequencing platform, Duplex Sequencing, for C. elegans for the first time. This will fulfill a significant goal of the training plan, which is to become proficient in computational biology and bioinformatics. We will also investigate the potential health effects on the organism, including mitochondrial function, reproduction, and lifespan as a consequence of mtDNA mutations. Overall, this research is impactful because it will provide better understanding of the role that exposures to environmental pollutants and genetic susceptibility play in the origin, signature, transmission, and effects of mtDNA mutations.