Where did the first Americans come from? Most researchers think Native American roots lie in Asia, although exactly where is not clear; but a few have suggested Europe, a decidedly minority view because today’s Native Americans have clear Asian ancestry. It turns out that both may be right, according to the latest ancient DNA evidence. A team based in Europe and the United States sequenced the entire genome from the skeleton of a boy who lived in Siberia 24,000 years ago (see photo), the oldest complete genome of a modern human to date. Surprisingly, the boy is closely related both to Eurasians and to Native Americans, but not to East Asians. So the researchers think that Native American ancestors with Eurasian roots might have interbred with East Asians sometime before making the journey over the Bering land bridge to the New World. The work, first reported by Science from a meeting in Santa Fe last month, is published today in Nature.