If you think way, way back to your high school biology class, you might remember a little cellular structure called the mitochondrion. Its claim to fame is that it’s the “powerhouse” of the cell — the organelle in charge of creating energy. But it also contains its own DNA, separate from the traditional DNA we think of, which lives in the nucleus of a cell. That nuclear DNA contains genetic information from both of our parents. But in mitochondrial DNA (mtDNA), that genetic information only comes from one parent.