Humans reached Asia in two waves

DNA extracted from a 40,000-year-old pinky bone and a 100-year-old lock of hair has provided glimpses of two Stone Age human migrations to Asia, including an early foray marked by interbreeding between ancient people and some mysterious, well-traveled members of the human evolutionary family.

Denisovans, an ancient humanlike population previously identified via nuclear DNA taken from a finger bone excavated in Siberia’s Denisova Cave, contributed a small portion of genes to living New Guineans, Australian aborigines, two aboriginal groups in the Philippines and populations on several nearby islands, say geneticist David Reich of Harvard Medical School in Boston and his colleagues.

Earlier analyses of modern human mitochondrial DNA, which is maternally inherited, had suggested that a single wave of humans took a southern coastal route from Africa to Asia around 65,000 years ago. Patterns of nuclear DNA alterations in an ancient Denisovan and in living groups in