Deoxyribonucleic acid (DNA) in the intracellular bodies known as mitochondria. It differs from nuclear DNA in its nucleotide sequences, its size (about 16.5 kb), and its source (it is derived solely from the egg, not the sperm). Variations in mtDNA point to the ways in which members of a related population differ from each other genetically.
A specific type of DNA present within mitochondria. Within human mitochondria, this DNA adopts a double-helical circular structure, encoding 13 proteins. Mitochondrial DNA possesses a unique genetic code, and its genomes remain unaltered by meiosis during reproduction. These attributes render mitochondrial DNA valuable for genetic investigations.
The importance of mitochondria possessing their independent DNA lies in the fact that disorders can be inherited through irregularities in mitochondrial DNA. Furthermore, the transmission of this DNA is exclusively maternal, directly from the egg.