Ancient infant DNA reveals how humans first moved into the Americas

Avatar By Joseph Scalise | 3 years ago

DNA taken from the skull of an ancient, six-week-old baby could help shed light on how early humans first populated the Americas, a new study published in the journal Nature reports.

The remains come from an 11,500-year-old child, who researchers unearthed from a burial pit in central Alaska. The girl — known as “sunrise girl-child” — is significant because she belonged to a previously unknown Native American population that descended from the first people to come to the Americas.

A group of international scientists uncovered part of the infant while digging at a prehistoric encampment in Alaska’s Tanana River Valley in 2013. By studying her DNA, the team managed to determine that a single ancestral Native American group split from East Asians about 36,000 year ago. Then, thousands of years later, they crossed the land bridge. From that point, the founding group split into two lineages roughly 20,000 years ago.

The first of those lineages — which were the ancestors of modern Native Americans — traveled south of the huge ice caps that covered much of North America between 20,000 and 15,000 years ago before spreading out across North and South America.

The infant analyzed in the study belonged to the newly identified second lineage, known as the Ancient Beringians. Researchers are not sure what happened to the population, but they do know they eventually disappeared and may have been absorbed into another group.

“The study provides the first direct genomic evidence that all Native American ancestry can be traced back to the same source population during the last Ice Age,” explained study co-author Ben Potter, a researcher at the University of Alaska Fairbanks, according to TIME.

These findings shed new light on human ancestors and gives researchers a better idea of how they spread across the world. Further study of the remains could help scientists get a better idea of ancient populations and finally know how early humans moved into the Americas. 

“We’ve established the oldest population was actually in Alaska, not elsewhere, so it’s very strong evidence for the Beringian land-bridge theory,” said study co-author Eske Willerslev, a researcher at the University of Copenhagen in Denmark, according to New Scientist.