CAMBRIDGE, MASSACHUSETTS—A genetic study has revealed that the Tupí-speaking Suruí and Karitiana, and the Ge-speaking Xavante peoples of the Amazon had an ancestor more closely related to indigenous Australasians than other present-day populations. “We’ve done a lot of sampling in East Asia and nobody looks like this. It’s an unknown group that doesn’t exist anymore,” Pontus Skoglund of Harvard Medical School said in a press release. Skoglund and population geneticist David Reich have labeled this ancestor group Population Y, after the Tupí word for ancestor, “Ypykuéra.” They think that Population Y and the so-called First Americans, whose DNA resembles that of today’s Native Americans, traversed the Bering land bridge into North America more than 15,000 years ago. “We don’t know the order, the time separation or the geographical patterns,” Skoglund said. The team would need DNA from a member of Population Y to determine how much it contributed to today’s Amazonians. “We have a broad view of the deep origins of Native American ancestry, but within that diversity we know very little about the history of how those populations relate to each other,” Reich said. To read about the earliest migration to the New World, go to "America, in the Beginning."