Researchers are studying ancient hunter-gatherer dna to gain insight into human longevity, potentially unlocking the secrets of living to 100 or more. The dna, which is thousands of years old, may hold clues about the evolution of modern humans and the factors that contribute to a long life. The study of ancient dna has also shed light on the lives and interactions of early human populations, although its findings may challenge existing timelines and understanding of human history.