Sunken body clue to American origins

The ancient remains of a teenage girl discovered deep underground in Mexico are providing additional insights on how the Americas came to be populated.

Divers found the juvenile's bones by chance in a vast, flooded limestone chamber on the Yucatan Peninsula.

Aged 15 or 16 at death, the girl lived at least 12,000 years ago.

Researchers have told Science Magazine her DNA backs the idea that the first Americans and modern Native American Indians share a common ancestry.

This theory argues that people from Siberia settled on the land bridge dubbed Beringia that linked Asia and the Americas some 20,000 years ago before sea levels rose.

These people then moved south to populate the American continents.