Lipid peroxidation and mtDNA degeneration. A hypothesis.

End-products of lipid peroxidation accumulate during the life of somatic cells. It is hypothesized that genotoxic intermediates of lipid peroxidation may have a role in causing age-associated DNA mutations. Such mutations are likely to accrue in the mitochondrial genome because it, unlike nuclear DNA, is not protected by histones and repair systems. In addition, it is located near the mitochondrial membrane where lipid peroxidation can be initiated by free radicals produced by the mitochondrial electron transport system. This idea is supported by in vitro experiments which show that mitochondrial DNA is damaged when mitochondria undergo lipid peroxidation.