One wave of migration from Siberia populated the Americas, DNA shows

Study also reveals some groups in South America have closer genetic ties to indigenous peoples of Australia, New Guinea and the Andaman Islands than to present-day Native Americans

Native American ancestors reached the new world in a single, initial migration from Siberia at most 23,000 years ago, only later differentiating into today's distinct groups, DNA research revealed Tuesday.

Most scientists agree the Americas were peopled by forefathers who crossed the Bering land and ice bridge which connected modern-day Russia and Alaska in Earth's last glacial period.