Genetic data of
skeleton confirms boy's ancestors orignated from Asia, researcher
more than 20 years anthropologists have debated whether the first
Americans arrived in the New World by walking over a land bridge
across the Bering Strait, as millions of schoolchildren have been
taught, or by sea from southwest Europe, perhaps in animal-skin
A new analysis challenges the out-of-Europe hypothesis, which
has figured in a political debate over the rights of present-day
Native American tribes. Scientists announced on Feb. 12 that they
had, for the first time, determined the full genome sequence of
an ancient American, a toddler who lived some 12,600 years ago and
was buried in western Montana. His DNA, they report, links todays
Native Americans to ancient migrants from easternmost Asia.
The study, published in the journal Nature, is the final
shovelful of dirt on the European hypothesis, said anthropological
geneticist Jennifer Raff of the University of Texas, co-author of
a commentary on it in Nature.
The idea that the first Americans arrived millennia earlier
than long thought and from someplace other than Beringia, which
spans easternmost Russia and western Alaska, has poisoned relationships
between many Native Americans and anthropologists. Some tribes fear
that the theory that the continents first arrivals originated
in Europe might cast doubt on their origin stories and claims to
ancient remains on ancestral lands.
Despite the new study, other experts say the debate over whether
the first Americans arrived from Beringia or southwestern Europe,
where a culture called the Solutrean thrived from 21,000 to 17,000
years ago, is far from settled.
They havent produced evidence to refute the Solutrean
hypothesis, said geneticist Stephen Oppenheimer of Oxford
University, a leading expert on using DNA to track ancient migrations.
In fact, there is genetic evidence that only the Solutrean
The partial skeleton of the 1-year-old boy, called Anzick-1,
was discovered when a front-end loader hit it while scooping out
fill in 1968. The grave and its environs contained 125 artifacts,
including stone spear points and elk antlers centuries older than
the bones, said anthropologist Michael Waters of Texas A&M Universitys
Center for the Study of the First Americans, a co-author of the
That suggests that the antler artifacts were very special
heirlooms handed down over generations, Waters said. Why they
were buried with the boy remains unknown.
The distinctive stone tools show that the boy was a member of
the Clovis culture, one of the oldest in North America and dating
to around 12,600 to 13,000 years ago. The origins and descendants
of the Clovis people have remained uncertain, but the boys
genome offers clues.
The genetic data from Anzick confirms that the ancestors
of this boy originated in Asia, said Eske Willerslev of the
Natural History Museum of Denmark, who led the study. The DNA shows
that the child belonged to a group that is a direct ancestor to
as many as 80 percent of the Native Americans tribes alive today,
he said: Its almost like he is a missing link
between the first arrivals and todays tribes.
The most likely scenario, said Texass Raff, is that humans
reached eastern Beringia from Siberia 26,000 to 18,000 years ago.
By 17,000 years ago, receding glaciers allowed them to cross the
Bering Strait. Some migrated down the Pacific coast, reaching Monte
Verde in Chile by 14,600 years ago, while others - including the
ancestors of Anzick-1 headed for the interior of North America.
genetic analysis found that the boy is less closely related to northern
Native Americans than to central and southern Native Americans such
as the Maya of Central America and the Karitiana of Brazil. That
can best be explained, the scientists say, if he belonged to a population
that is directly ancestral to the South American tribes.
Todays Native Americans are direct descendants of
the people who made and used Clovis tools and buried this child,
the scientists wrote. In agreement with previous archaeological
and genetic studies, our genome analysis refutes the possibility
that Clovis originated via a European migration to the Americas.
Not all experts are convinced. We definitely have some
stuff here in the east of the United States that is older than anything
they have in the west, said anthropologist Dennis Stanford
of the Smithsonian Institution, a proponent of the out-of-Europe
model. Theyve been reliably dated to 20,000 years ago,
too early for migrants from Beringia to have made the trek, he said,
and strongly resemble Solutrean artifacts.
Genetic analysis is also keeping the out-of-Europe
One variant of DNA that is inherited only from a mother, called
mitochondrial DNA, and is found in many Native Americans has been
traced to western Eurasia but is absent from east Eurasia, where
Beringia was before the sea covered it, Oppenheimer explained. For
the variant, called X2a, to have such a high frequency in Native
Americans it must have got across the Atlantic somehow,
he said. The new study completely ignored this evidence, and
only the Solutrean hypothesis explains it.
The scientists hope the Anzick boy has yielded all his secrets:
He will be reburied by early summer.