Fossilized feces tell an old tale

Courtesy of Dennis LeRoy Jenkins

DNA and proteins recovered from these 14,300-year-old coprolites suggest humans reached the New World 1,000 years before the oldest-known Clovis site.

For decades, scientists have bestowed bragging rights of being the first people to settle in the New World on the Clovis culture, a society known only by the artifacts they left behind. New genetic evidence extracted from fossilized human waste now suggests humans entered North America more than 1,000 years before the establishment of the oldest-known Clovis site.

While excavating in the Paisley Caves of southern Oregon in 2002 and 2003, archaeologists led by Dennis Jenkins of the University of Oregon in Eugene discovered 14 coprolites — fossilized excrement — that appeared to be human based on their size, shape and color. They collected the coprolites and sent them to Eske Willerslev and Thomas Gilbert of the University of Copenhagen in Denmark to analyze for traces of human DNA. About half the samples contained genetic signatures unique to Native Americans. To rule out contamination from the researchers, their DNA was also analyzed. None was a match to the DNA extracted from the coprolites.

Some of the samples contained DNA from coyotes or dogs, but the researchers think the coprolites are indeed human because they contained human proteins, they reported online in Science on April 3. The canine DNA, they wrote, may simply be the result of dogs urinating on the feces.

Using radiocarbon dating, the team determined that the coprolites are about 14,300 years old. The oldest-known Clovis site is only 13,000 years old. But because the coprolites were not found with any surrounding artifacts, it’s hard to know whether these early North American inhabitants had any ties to the Clovis culture or if they represent a separate, earlier migration into the New World.

Erin Wayman

Links:
"Clovis first" in doubt, Geotimes, May 2007
The Ice-Free Corridor Revisited, Geotimes, February 2004

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