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The
genome sequence of a male infant who lived 12,600 years ago
from a Clovis burial site (shown here with poles) in Wilsall,
Mont., suggests many contemporary Native Americans are direct
descendants of the people who made and used Clovis tools.
(photo by Mike Waters)
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A prehistoric boy's DNA now suggests that ancient toolmakers long
thought of as the first Americans may serve as a kind of "missing
link" between Native Americans and the rest of the world, researchers
say.
The findings reveal these prehistoric toolmakers are the direct
ancestors of many contemporary Native
Americans, and are closely related to all Native Americans.
Scientists investigated a prehistoric culture known as the Clovis,
named after sites discovered near Clovis, N.M. Centuries of cold,
nicknamed the "Big
Freeze," helped wipe
out the Clovis, as well as most of the large mammals in North
America. The artifacts of the Clovis are found south of the giant
ice sheets that once covered Canada, in most of North America, though
not in South America.
The stone tools of the Clovis, such as distinctive fluted or
grooved spear points, date to about 12,600 to 13,000 years ago,
making them the oldest widespread set of artifacts in North America.
For most of the past 50 years, archaeologists thought the Clovis
were the first Americans, but investigators recently uncovered
evidence that humans
were in the New World before Clovis, at least more than 14,000
years ago.
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A
nearly complete projectile point of dendritic chert, a mid-interval
biface of translucent quartz, displaying relatively heavy
red ochre residue and an "end-beveled" osseous rod, also exhibiting
red ochre residue. These artifacts are technologically consistent
with artifacts of the Clovis complex. (photo by Sarah L. Anzick)
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Researchers focused on bones unearthed by construction next
to a rock cliff on the land of the Anzick family in central Montana.
[See
Images of Clovis Culture Artifacts]
"I was just a small child in 1968 when the only Clovis burial
site was identified accidentally on my parents' property in Wilsall,
Montana,"study co-author Sarah Anzick at Rocky Mountain Laboratories
in Hamilton, Mont., told Live Science.
Anzick boy
The so-called Anzick skeleton was found with about
125 artifacts, including Clovis fluted spear points and tools made
from antlers, and covered in red ochre, a type of mineral.
"This is the oldest burial in North America, and the only known
Clovis burial,"study co-author Michael Waters at Texas A&M University
in College Station told Live Science.
"Genetic studies tell us these were the remains of a boy," Waters
said. "Physical anthropological studies tell us he was 1 to 1.5
years old, and radiocarbon dating tells us this burial took place
about 12,600 years ago, at the end of the Clovis era." It remains
uncertain how this child died.
The scientists analyzed DNA from the bones. They managed to
recover the first complete genome sequence of an ancient North American,
despite how badly preserved the DNA in the remains were. [Top
10 Mysteries of the First Humans]
"We found the genome of this boy is closely related to all Native
Americans of today than to any other peoples around the world,"
study co-author Eske Willerslev of the University of Copenhagen
in Denmark told Live Science. "We can also see from the genome study
that this Anzick population is the direct
ancestor to many Native Americans to date. As such, our study
is in agreement with the view that present-day Native Americans
are direct descendants of the first peoples in the Americas."
Shane Doyle, study co-author at Montana State University, said,
"I feel like this discovery confirms what tribes never really doubted
that we've been here since time immemorial and that all of
the artifacts in the ground are remnants of our direct ancestors."
It was surprising that the Anzick lineage "is directly ancestral
to so many peoples in the Americas," Willerslev said. "We don't
have genetic information by any means from all tribes, but a very,
very broad estimate suggests 80 percent derives from the Anzick
group, which is an amazing result almost like a missing link,
if you want."
The first Clovis
The origin of the Clovis was uncertain. Although it
was generally believed the Clovis ultimately derived from Asia,
others suggested the ancestors of the Clovis actually may have come
from southwestern Europe between 21,000 and 17,000 years ago, the
so-called "Solutrean hypothesis."
This new research "has settled the long-standing debate about
the origins of the Clovis," Willerslev said. "We can say the Solutrean
theory suggesting Clovis originated from people in Europe doesn't
fit our results."
These genetic findings "seem to fit quite nicely with an early
occupation of the Americas about 2,000 years before the onset of
Clovis," Waters said. "If you look at credible evidence for the
peopling of the Americas, most date from a period 15,000 to 14,500
years ago," although "there are claims of occupation 20,000 to 30,000
years ago."
The scientists also discovered evidence of a deep genetic divergence
that occurred between northern Native American groups and those
from Central and South America that happened before the Clovis era.
Specifically, although most South Americans and Mexicans are part
of the Anzick lineage and therefore Clovis, northern Canadian groups
belong to another lineage.
Intriguingly, while the Anzick skeleton dates back 12,600 years
to the twilight of the Clovis era, the antler tools date back about
13,000 years to the dawn of the Clovis era. In addition, "genetic
work shows the antler
tools were made of elk, a rare animal in the plains at that
time," Waters said. The difference in age between the skeleton and
the antler tools, as well as the fact that the antlers were from
a rare animal, suggest the antler tools were "very special ritual
objects passed down for generations."
The remains will be reburied.
"We're excited and honored to work with the tribes
and plan a reburial ceremony to lay this child to rest with the
respect such an important part of human
history deserves," Anzick said. The ceremony is planned for
late spring or early summer of this year.
"The genetic information provided by the Anzick boy is part
of the larger story of modern humans," Waters said. "We know that
modern humans originated in Africa and 50,000 years ago spread rapidly
over Europe and Asia. The last continents to be explored and settled
by modern humans were the Americas. In essence, the Anzick boy tells
us about the epic journey of our species."
The scientists detailed their findings in the Feb. 13 issue
of the journal Nature.
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