What is mitochondrial DNA?
Most of the deoxyribonucleic acid (DNA) within cells of eukaryotic organisms is confined to the membrane-bound nucleus. The majority of cellular organelles do not have their own DNA. The fact that mitochondria do contain DNA is part of the evidence that leads scientists to believe that the ancestors of this organelle were once independent prokaryotic cells. The DNA within mitochondria is called mtDNA, and each mitochondrion is estimated to contain 2-10 copies. In the cells of modern day organisms, the genes that were originally found in that symbiotic prokaryotic cell are now also present in our nuclear DNA, having since been transferred to the eukaryotic nucleus through the course of evolution (Campbell & Reece).
