Autophagy has emerged as a novel mechanism for tumor suppression. It has been postulated that defective autophagy leads to the accumulation of damaged proteins or organelles, resulting in genome instability and cancer. We have observed that a Bcl-2 family member, Nix, is required for selective autophagy of mitochondria that have lost mitochondrial membrane potential. Dysfunctional mitochondria can produce reactive oxygen species to cause DNA damage. However, it is unclear whether selective mitochondrial autophagy is important for preventing damages to mitochondrial and nuclear DNA. We hypothesize that selective mitochondrial autophagy plays a critical role in mitochondrial quality control. Accumulation of dysfunctional mitochondria due to defective autophagy may cause increases in DNA damage, leading to genome instability. We propose 1) to determine the role for mitochondrial autophagy in protecting genome stability;2) to characterize the molecular mechanisms of specific recognition of dysfunctional mitochondria by autophagosomes. This study may help to reveal molecular events of autophagy as novel biomarkers for mitochondrial quality control in the protection against genome instability and cancer. PUBLIC HEALTH RELEVANCE: Narrative This study seeks to identify the molecular events in autophagy as novel biomarkers in mitochondrial quality control and the prevention of genome instability.