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An explanation of aging that is now rising to prominence attributes the root cause of human aging to the accumulated deletion mutation damage to mtDNA (mitochondrial DNA). Mitochondria are the bacteria-like organelles within cells that produce ATP for cell energy. Only 13 of the mtDNA genes actually code for proteins, while the other 24 genes all support the local ribosomal production of these proteins within the mitochondrion. This suggests an interesting question first proposed by de Grey: Since most of the genes coding for mitochondrial components have already been moved by evolutionary pressure to the safer domain of nuclear DNA,