Many humans live to see their 80s, some even reach 100. But chimpanzees rarely make it past 50, despite sharing 99% of our genetic code. While modern medicine has added years to human lifespans, a study points to a more ancient explanation why humans are the long-lived primate. Part of the secret to human longevity may lie in chemical changes to our DNA that slowed the rate of aging after human ancestors diverged from chimps.
