Based on the results, researchers show evidence of several human migrations into South America, including two previously unknown to science.
Studying ancient DNA adds extra detail to this picture, revealing the presence of genetically distinct groups who didn't leave behind unique physical traces.
The other branch—sometimes called the Southern Native Americans—rapidly moved south about 14,000 years ago, becoming the main ancestors of today's indigenous Central and South Americans.
While his team also saw migrations into South America 14,000 years ago, they found signs that a group living in Mexico or Central America spread out 8,700 years ago into South America and northward into what is now the U.S. Great Plains.
Comparing these DNA sequences revealed that the Andes' lowland and highland peoples split about 8,750 years ago, give or take a few centuries.