Mitochondria are structures within cells that convert the energy from food into a form that cells can use. Although most DNA is packaged in chromosomes within the nucleus, mitochondria also have a small amount of their own DNA. This genetic material is known as mitochondrial DNA or mtDNA. In humans, mitochondrial DNA spans about 16,500 DNA building blocks (base pairs), representing a small fraction of the total DNA in cells.
Mitochondrial DNA contains 37 genes, all of which are essential for normal mitochondrial function. Thirteen of these genes provide instructions for making enzymes involved in oxidative phosphorylation. Oxidative phosphorylation is a process that uses oxygen and simple sugars to create adenosine triphosphate (ATP), the cell's main energy source. The remaining genes provide instructions for making molecules called transfer RNA (tRNA) and ribosomal RNA (rRNA), which are chemical cousins of DNA. These types of RNA help assemble protein building blocks (amino acids) into functioning proteins.
Mitochondrial genes are among the estimated 20,000 to 25,000 total genes in the human genome.
How are changes in mitochondrial DNA related to health conditions?
Many genetic conditions are related to changes in particular mitochondrial genes. This list of disorders associated with mitochondrial genes provides links to additional information.
The following conditions are related to changes in the structure of mitochondrial DNA. cancers Mitochondrial DNA is prone to somatic mutations, which are a type of noninherited mutation. Somatic mutations occur in the DNA of certain cells…