Human DNA found in 14,000 year-old feces

(UWIRE)University of Oregon archaeologist Dennis Jenkins has heard all the poop jokes before. Some of them he won’t even repeat.

“I’ve heard a bunch of them, let me assure you,” Jenkins said. “All of my friends are ruthless when it comes to this stuff.”

The friendly ridicule is the result of findings made by Jenkins and a team of international researchers, who uncovered and identified samples of human feces that date to more than 14,000 years ago – older than any human DNA previously found in the Americas.

But the discovery is also prompting international attention from other scientists and media. During the past two weeks, Jenkins alone has kept a tally of 32 media interviews he’s done since the findings were released, and he’s been involved in at least two documentary films about the subject.

“It’s good to feel like you’ve done good work,” Jenkins said. “But it’s very ephemeral. It’s news, and when it’s no longer news, then everyone will go back and I’ll be able to go back to work.”

For Jenkins and his team, the unprecedented discovery was years in the making. The samples were first collected from the Paisley Caves in southeast Oregon during the summer of 2002, on one of three research trips Jenkins and his University field groups made to the site in recent years.

The group found the excrement samples – known as coprolites -among other animal remains in the area. Jenkins didn’t know at the time whether they were human.

“It looked human, but I didn’t have the knowledge,” he said. “It was the right size, it was the right color, it was the right shape, but … I wasn’t an expert.”

Dustin Kennedy, a 2002 University graduate who was involved in the three Paisley Caves excavations in 2002, 2003 and 2007, said researchers weren’t fully aware of the samples’ ages, either.

“Any time that we were coming across the coprolites, it wasn’t even occurring to us that they could be preserved for that long,” Kennedy said.

More than a year later, Danish geneticist Eske Willerslev was sent to examine the samples. He found Native American DNA in the coprolite after another year of analysis.

Researchers then screened the results to ensure it didn’t match the DNA of 55 University students who were on the original excavation and 12 workers in the Denmark lab.

After several more months of independent analysis and carbon dating, Jenkins had his results in late 2006. The samples were 14,300 years old, predating the Clovis culture originally thought to be the first to inhabit North America.

“People have asked me, ‘Why haven’t you published this before?'” Jenkins said. “Well, I didn’t want to be marginalized. This is radical stuff, so I wanted this to be accurate, and I wanted it to be accepted as much as possible the first time around.”

Eventually, Jenkins became a lead author on a research article that was published in Science magazine this month. The media frenzy started shortly before that, he said.

The discovery also provides positive exposure for the University as a whole, said Jon Erlandson, director of the University’s Museum of Natural and Cultural History.

“Dennis has put the pieces together with the DNA and the state-of-the-art dating … I think the Clovis-first model is dead at this point, and that’s big news,” Erlandson said. “And to have it happen right here at the U of O is exciting.”

Erlandson, who also has a background in archaeology, said he would like to put the samples on display in the natural history museum. Though displays are typically determined as far as two years in advance, it’s likely the items will be considered in the future, he said.

The lengthy research of each sample has also created an important fusion between DNA analysis and archaeology, said Kennedy, now a research assistant with the natural history museum. Where before, archaeologists wouldn’t be likely to think to have an artifact tested for DNA, now they might be more careful not to contaminate an item for future lab and DNA analysis, he said.

“It’s going to really change how both of those things are done,” Kennedy said.

Jenkins said he hopes the recent findings are only the first step in continuing research at the Paisley Caves site.

“We have just scratched the surface,” Jenkins said. “Now we know it’s there, and we can go back and really begin to do the interesting stuff.”

Some of that research will include further analysis of the 2002 findings, he said. Researchers could also look at coprolites already collected in greater detail and do further excavations at the site, possibly determining the ancient site’s demographic breakdown between males and females, or what inhabitants ate.

Jenkins is also using the recognition to secure funding for future visits to the caves that could provide a better understanding of their history.

“What I hope,” Jenkins said, “is that this exposure will make the local people really have a sense of pride about it and want to protect it.”

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