Mitochondrial DNA (mtDNA)

Mitochondria are cell organelles which contain mitochondrial DNA. These organelles are important as they produce the energy needed for the cell to function. All the food we take in must be converted into a usuable form of energy for the cells. What the Mitochondria in fact do is convert food energy into adenosine triphosphate (ATP). Normal DNA is contained within what is known as the cell nucleus, the part of the cell which controls everything, or sometimes referred to as the “control centre” of the cell. Mitochondrial DNA is not the same as nuclear DNA. MtDNA, as it is sometimes referred to, is DNA inherited from the mother and believed to play a key role in the ageing process and diseases associated with old age. Mitochondrial DNA is found in all cells in the human body except for red blood cells. Moreover, it is also found in samples of cut hair which means that whilst a cut hair sample cannot yield any nuclear DNA, the sample can produce an MtDNA profile.

The mitochondrial DNA genome is the second genome in human beings. Most people asssume we only have genome (the nuclear DNA genome). MtDNA contains about 16,000 DNA blocks but is comparatively a tiny portion of the total cell DNA. Ancestry testing and relationship testing through the female line is also done by means of MtDNA. MtDNA is passed from a mother to her children, both male and female, but is not passed from males to their children. In all mamals, MtDNA is solely inherited down the maternal line. Some insects and molluscs are exceptions as studies have shown that sometimes males too pass their MtDNA to their offspring.

MtDNA testing is often used to draw up a DNA profiles in cases where there is a victim of a crime or disaster in which the nucleus DNA was destroyed. Forensic laboratories often use MtDNA for identification of human remains. Our Relationship DNA Testing Services will provide further insight into this particular type of testing.