Accumulation of deletions in human mitochondrial DNA during normal aging: analysis by quantitative PCR

We have developed a quantitative PCR technique to measure the amount of a specific mitochondrial DNA deletion (ΔmtDNA), the so-called ‘common deletion’, in human tissues. Using this method, we estimate that there is a 10 000-fold increase in this ΔmtDNA species in muscle during the course of the normal human lifespan. The maximum amount of common deletion observed in aged muscle was approx 0.1%. Tissues that turn-over slowly, such as skeletal muscle and heart, contained more ΔmtDNA than more rapidly dividing tissues, such as a liver, in agreement with studies performed by others.