STEVE INSKEEP, HOST:
Bones and artifacts have told the story of the people who migrated to the Americas from Siberia about 15,000 years ago. These ancient migrants are believed to be the distant ancestors of the people who spread across North and South America in the millennia before Europeans arrived, from the Inuit to the Cherokee to the Maya and many more. Now that story is bolstered with some dramatic ancient DNA. Scientists say they have decoded the genome of a baby who died in present-day Montana more than 12,000 years ago. NPR's Richard Harris reports.
RICHARD HARRIS, BYLINE: The baby, a one year old boy, is the only human skeleton known from a brief but prolific culture in the Americas called Clovis.
MICHAEL WATERS: Clovis is what we like to refer to as an archeological complex.
HARRIS: Michael Waters at Texas A&M says that complex is a set of tools made of bone and stone. Those artifacts were common for about 400 years, starting about 13,000 years ago. There is only one set of human remains associated with those tools - an infant who was buried along with more than 100 artifacts in present day Montana. Now scientists have been able to read the DNA taken from that precious discovery.
WATERS: So this genetic study actually provides us with a look at who these people were.
HARRIS: The most obvious conclusion from the study, reported in Nature magazine, is that the Clovis people who lived on the Anzick site in Montana were genetically very much like Native Americans throughout the western hemisphere.
ESKE WILLERSLEV: The Anzick family is directly ancestral to so many peoples in the Americas. I mean, that's astonishing.
HARRIS: Eske Willerslev led the effort to read that genome from his lab in Copenhagen. The genes reveal that early Americans are the product of two lineages that most likely met and interbred in Asia before making the trek across the Bering land bridge. Michael Waters says this helps clarify the relationship among Native Americans.
WATERS: So this strongly suggests that there was a single migration of people into the Americas. And these people were probably the people who eventually gave rise to Clovis.
HARRIS: This finding contradicts a long-shot hypothesis that that Clovis's ancestors actually came from Europe, not Asia. But it leaves many other questions about Clovis unresolved. The artifacts from this culture are found from Washington State to Florida and many places in between. But the culture also disappeared suddenly, around 12,600 years ago. Waters doesn't find that too mysterious.
WATERS: People change all the time and cultures change all the time and technologies change. And they change because people are adapting to new environments and changes in climate. And at the end of the Clovis time period, around 12,600 years ago, when this child was buried, you know, the climate was changing. It was the beginning of the Younger Dryas cold snap. This is when you start seeing a lot of cultural differentiation taking place.
HARRIS: The DNA now makes it clear that the people who used Clovis tools lived on, even though they left their old technology behind. But Eske Willerslev says the Clovis genes give only a broad-brush view of how and when migrations throughout the Americas took place.
WILLERSLEV: We have no idea exactly where the U.S. fits in this pattern, and to be completely honest, we have no idea how they actually moved through time, these different groups across the continent. In order to answer that question, there's only one way to go, and that is actually sequencing more genomes from ancient remains.
HARRIS: That will require, among other things, cooperation with native peoples. In the case of the Clovis child, the archeologists worked closely with modern tribes to make sure they were treating the remains appropriately. They say the Clovis infant will be reburied on the property where he was unearthed later this year. Richard Harris, NPR News.
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