human longevity

In a study of nonrelated people who have lived for a century or more, the researchers found that the centenarians had something in common: each was five times more likely than the general population to have the same mutation in their mitochondrial DNA (mtDNA). That mutation, the researchers suggest, may provide a survival advantage by speeding mtDNA replication, thereby increasing its amount or replacing that portion of mtDNA which has been battered by the ravages of aging.