What is the age of the age-related mutations in mitochondrial DNA?
Harvard Medical School, Boston, USA The Mitochondrial Theory of Aging postulates that mutations in mitochondrial DNA accumulate with age and cause various intracellular adverse effects that ultimately contribute to some age-related degenerative changes. It is usually assumed that the mutations in question are actually generated at old age. Analysis of mutational spectra (i.e. frequency distributions of mutations by kind), however, suggests that at least in some cases mutations that are observed at old age may have been originally generated early in the development. In particular, one observes large variation of mutant frequencies from sample to sample and from individual to individual. If mutations were generated in old tissues, the large number of mutational events should be sufficient to create a stable mutational spectrum, where mutant frequencies are proportional to mutational rates. Mutational rates however, depend on biochemical reactions that should not change from one location
