Mitochondria are the powerhouse of the cell. Distinctively, they contain their own DNA termed Mitochondrial DNA (mtDNA).

Each mammalian cell contains thousands of copies of mtDNA. When all copies within a cell are identical, the cell exists in a state known as “homoplasmy”. Sometimes, a mutation might occur in a copy of mtDNA. Because there are so many copies, the muated form can coexist with the wildtype form in a state known as “heteroplasmy”.

Author: Alan Foley (ESR2)