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 (delta mtDNA), the so-called 'common deletion', in human tissues. Using this method, we estimate that there is a 10,000-fold increase in this delta mtDNA 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 delta mtDNA than more rapidly dividing tissues, such as liver, in agreement with studies performed by others.