What is mtDNA (Mitochondrial DNA)?
mtDNA (Mitochondrial DNA) is the small circular genome inside mitochondria, encoding proteins essential for the electron transport chain. Unlike nuclear DNA, mtDNA has limited repair mechanisms and is exposed to high concentrations of reactive oxygen species from OXPHOS, making it vulnerable to damage.
Key Points
- •Maternal inheritance — mtDNA is passed primarily through the maternal line
- •Mutation rate — higher than nuclear DNA due to oxidative stress
- •Red light — photobiomodulation has been studied in cells and animals for effects on mtDNA and biogenesis; this is not shown in people
Why does mtDNA matter?
mtDNA matters because it carries genes mitochondria need to produce energy. Although most mitochondrial proteins are coded in the cell nucleus, mtDNA encodes several key parts of the energy-producing chain, so errors in it can reduce a cell's energy supply.
It is inherited almost entirely from the mother, which makes it useful for tracing maternal ancestry and in forensic identification. Each cell holds many copies, and cells can contain a mix of normal and altered copies, a situation called heteroplasmy. The proportion of altered copies helps determine whether problems appear.
What happens when mtDNA goes wrong?
When mtDNA carries harmful mutations, the result can be a mitochondrial disease. These conditions tend to affect tissues with high energy demand, such as the brain, muscles, heart, eyes, and ears. Examples include Leber hereditary optic neuropathy and MELAS syndrome.
Symptoms vary widely, even within the same family, because the share of mutated copies differs between people and tissues. mtDNA damage also accumulates with age and has been studied as a contributor to aging and age-related disease, though its exact role is still debated. Diagnosis involves genetic testing through specialists.
In ONDA Life
The Mitochondrial DNA Red Light article covers protocols for supporting mitochondrial health and mtDNA.