Unlike DNA in the nucleus of cells, mitochondrial DNA evolves quickly. (sciencemag.org)
But DNA strands are too thin to be tracked under the microscope, and even if that were possible, you'd have the vast amount of DNA in the nucleus to contend with. (sciencedaily.com)
This DNA is found in the nucleus of the cell, which serves as the «command center» of the cell, as well as in the mitochondria. (healingdaily.com)