Objective: UPlanSApo 100x oil/1.40	Exposure: 300 ms
Microscope: Olympus DSU/IX81	Gain: 3
Camera: Hamamatsu ImagEM	Interval: 2 s

Though originally thought to be inherited strictly through the maternal line, mitochondrial DNA may, in rare instances, be paternally inherited. Mitochondria act as an energy source in the tail of the sperm, and when the sperm reaches and attaches to the egg for fertilization, the tail usually falls off along with the mitochondria, leaving only the mitochondria in the egg to be passed on to another generation. Mitochondrial DNA does not get shuffled in every generation like nuclear DNA, making it a useful tool for the study of human evolution due to its slow rate of change. Forensic science uses mitochondrial DNA to identify murder victims and doctors have implicated mitochondrial DNA in many genetic diseases including Alzheimer's disease and diabetes. In the digital video presented above, normal Gray fox lung fibroblast cells (FoLu line) are expressing mEGFP fused to the mitochondrial targeting signal from subunit VIII of human cytochrome C oxidase.