Clovis presence in North America. The reading of an obsidian flake and
a duck bone have been dated to 16,000 years ago, going back some
before the 14,000 years ago for the coprolites.
By Jeff Barnard
THE ASSOCIATED PRESS
PAISLEY, Ore. -- For some 85 years, homesteaders, pot hunters and
archaeologists have been digging at Paisley Caves, a string of shallow
depressions washed out of an ancient lava flow by the waves of a lake
that comes and goes with the changing climate.
Until now, they have found nothing conclusive -- arrowheads, baskets,
animal bones and sandals made by people who lived thousands of years
ago on the shores of what was then a 40-mile-long lake, but is now a
sagebrush desert on the northern edge of the Great Basin.
But a few years ago, Dennis Jenkins, a University of Oregon
archaeologist, and his students started digging where no one had dug
before. What the team discovered in an alcove used as a latrine and
trash dump has elevated the caves to the site of the oldest
radiocarbon-dated human remains in North America.
Coprolites -- ancient feces -- were found to contain human DNA linked
directly to modern-day Native Americans with Asian roots and
radiocarbon dated to 14,300 years ago. That's 1,000 years before the
oldest stone points of the Clovis culture, which for much of the 20th
century was believed to represent the first people in North America.
The idea that coprolites contain valuable information is not new, but
extracting DNA from them is. When the findings were published this
year in the journal Science, they plopped Jenkins and his colleagues
in the middle of one of the hottest debates in North American
archaeology. Just when did people first come here, and how did they
get here?
For many years the prevailing view was that the Clovis people walked
from Siberia to Alaska across a land bridge exposed by the Ice Age and
spread south through an ice-free corridor down the center of the
continent exposed 10,000 years ago by warming temperatures.
The Paisley coprolites indicate that people had found another way,
perhaps crossing the land bridge but then walking down the coast, or
even crossing the ocean by boat, the way people went from New Guinea
to Australia thousands of years earlier. The findings kill the
suggestion that some of the earliest Americans came from Europe. And
they almost didn't get to tell their story.
Bill Cannon calls himself a "used archaeological site salesman," but
is really the U.S. Bureau of Land Management's Lakeview District
archaeologist. Cannon knew that Luther Cressman, a University of
Oregon archaeologist, had dug here in the 1930s, as did numerous
looters.
Cannon can show you the rusty nail Cressman drove into the wall of
Cave No. 2 as his data point, from which the locations of artifacts
are measured, as well as recent illicit excavations.
Cressman found evidence -- a dart point, basketry, sandals and animal
bones -- that people were here before Clovis and that they hunted
large animals. But he could make no strong conclusions, and he saved
no coprolites.
Cannon could see that there was a lot that hadn't been dug, and
figured that Jenkins was the guy to do it.
Jenkins is a senior research associate at the University of Oregon
Museum of Natural and Cultural History and the head of its Northern
Great Basin Archaeological Field School. His office in a Quonset hut
on the campus in Eugene is decorated with the antlers of mule deer he
shot in the high desert east of the Cascade Range. His arm carries a
tattoo from a motorcycle club in Las Vegas, where he grew up and went
to college.
Jenkins has never found one of the distinctively shaped, fluted, stone
spear points that mark the Clovis culture, named for a site near
Clovis, N.M., uncovered in 1929. But in three digs at Paisley -- 2002,
2003 and 2007 -- Jenkins has gathered 700 coprolites, perhaps a third
of them human.
The coprolites contain pollen, seeds, chipmunk bones, sage grouse
feathers, trout scales, things that ancient people would have been
eating, but Jenkins couldn't be sure that they weren't coyote. He had
estimated their age at 1,000 years before Clovis from dating bone and
obsidian flakes found nearby.
Unlike bone, obsidian cannot be radiocarbon dated. But the time since
a flake was broken off can be estimated from how far moisture has
penetrated, leaving a visible band. The distance depends on
temperature, so to refine the measurements, archaeological consultant
Tom Origer and his team from Santa Rosa, Calif., tracked the
underground temperatures for a year.
At $600 a shot, Jenkins still didn't want to get any of the coprolites
radiocarbon dated until he knew they were human.
Then in the fall of 2003, he received an unexpected e-mail from Alan
Cooper of Oxford University, who was looking for sites to test with
techniques he was developing to extract ancient DNA from soils.
Cooper and Jenkins arranged for Eske Willerslev, then a Danish
postdoctoral fellow working for Cooper at Oxford, to deliver a paper
on his work with ancient DNA before the Northwest Anthropological
Conference. They also wanted Willerslev to pick up some samples from
Paisley Caves.
In 2003, Willerslev extracted from Siberian permafrost DNA of
mammoths, bison and mosses that proved to be 300,000 to 400,000 years
old. More recently, he teased out DNA from silt-crusted ice cores from
Greenland that showed forests, beetles and butterflies had lived
800,000 years ago where a glacier stands today.
Willerslev took home 14 coprolites, though he was not very interested.
"To identify if humans were using caves as a toilet, I didn't see that
as important," he said.
For years, they sat in a freezer at Oxford. Willerslev took them with
him when he took a professorship in biology at the University of
Copenhagen, and in 2006 turned them over to a graduate student who
needed a project. She found DNA from two of the five Native American
genetic groups. Both have links to Asia.
Radiocarbon dating -- at two different labs -- showed three were more
than 14,000 years old.
"It is the oldest evidence of human presence" in North America, said
Willerslev, now director of the Center for Ancient Genetics at the
Copenhagen school.
Vance Haynes, a professor emeritus of geoarchaeology at the University
of Arizona, has spent his career studying the Clovis people.
While there is a growing body of evidence and acceptance of the idea
that people were in North America before Clovis, the evidence remains
skimpy and confusing, with no coherent thread like a common way of
flaking obsidian into spear points, he said.
He would like to see dates further confirmed by another radiocarbon
dating because if it is accurate, the find offers important evidence
that early people traveled down the coast as they spread through the
continent, and then moved east, and did not need the ice-free
corridor.
Jenkins figures that the caves have much more to tell. An obsidian
flake and a duck bone have been dated to 16,000 years ago. And he
can't wait to dig beneath some boulders that apparently fell from the
roofs of the caves between 7,000 and 9,000 years ago, guarding
whatever lies below from looters and other archaeologists.
When Jenkins returns, probably next spring, the diggers will be
dressed like technicians in a silicon-chip plant with face masks,
latex gloves and bunny suits to reduce the chances of contamination,
making it possible to analyze the DNA with greater resolution. The
coprolites could reveal how many individuals lived in the caves at any
one time, how many were men and how many women, how closely they were
related, and even what time of year they were there.
"It raises the hair on the back of my neck to think what they
destroyed and had no clue," Jenkins said of those who dug before him.
"In the process of digging this to get artifacts, they throw out
coprolites that had so much information in them."
http://www2.journalnow.com/content/2008/dec/04/dna-secrets
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