英文版新闻： http://www.parade.com/news/2010/06/13-who-were-the-first-americans.html Who Were the First Americans? by Stephen Fried 06/13/2010 Who really discovered America? If you think the earliest Americans were Christopher Columbus and his crew, or even the Native Americans they met here, you’d be off by thousands of years. The debate over just how many years—and how people lived after arriving here—is one of the most important in ancient U.S. history. The hunt for “the American Adam,” says David Meltzer, a professor of prehistory at Southern Methodist University, is a “search for insight into how our species adapted to a truly new world.” For much of the last century, scientists thought the earliest Americans got here 13,000 years ago, based upon spear points and bone tools found near Clovis, N.M. It was hypothesized that they came from Asia, walking across a land corridor that existed between Siberia and Alaska. After Clovis, other archaeologists thought they'd uncovered evidence of a still-earlier culture, but, ultimately, their claims always fell apart. Then, in 2002, scrappy ex-biker turned archaeologist Dennis Jenkins of the University of Oregon’s Museum of Natural and Cultural History began digging in his state’s Paisley Caves. He and his team uncovered a few bones of extinct species of horse and camel and also fossilized excrement, or “coprolites” in scientific-speak. He took the samples back to his lab and forgot about them. Four years later, Danish evolutionary biologist Eske Willerslev, an expert in ancient DNA, analyzed some coprolites he had taken from Jenkins’ lab for study. (Like our sweat and saliva, our excrement contains DNA.) He called Jenkins with amazing news: At least six of the samples had recognizable, intact human DNA with genetic markers linking them to ancient Native American, Siberian, and Asian peoples. Radiocarbon dating placed them at 14,300 years old, over 1000 years earlier than the Clovis find. Willerslev and Jenkins’ results were published in Science in 2008, and many archaeologists, even some who had defended the “Clovis-first” model, accepted their authenticity. However, the mainstream press fixated on the fact that the groundbreaking remains were nothing more than prehistoric human waste. So Jenkins got a nickname. “Yes,” he laughs, “they call me Dr. Poop.” Jenkins was cautious about his finds. “I know,” he says, “how many archaeologists thought they changed the dominant Clovis paradigm, and they failed every time.” Because some critics have said the Paisley coprolites could have come from animals—according to Jenkins, protein tests confirm they are indeed from humans—he knows that he must find artifacts fashioned by human hands to prove he has truly discovered the earliest Americans. Last summer, I traveled to central Oregon to see the dig for myself. Standing at the mouth of Paisley Cave #5—its low, jagged roof creating the feeling of being inside a T-Rex’s jaws—I can see why people might have stopped there. The eight interconnected caves are the only shade, shelter, and protected elevation for miles. The work begins before 8 a.m. every day. It is methodical, dirty, and periodically stinky. Jenkins roams among the caves, conferring with the students and volunteers who are digging down five to 10 feet. He wants the artifacts found and photographed exactly where they were underground —a nd not in the buckets of dirt screened later. At 9:15 one day, we hear a commotion from Cave #2—a dust-caked student thinks she sees a coprolite. To prevent contamination, a sweaty student strips down to briefs and dons a white Tyvek protective suit and latex gloves. He grasps the specimen with sterile disposable forceps and gently lowers it, like a piece of plutonium, into a specimen cup. Among the most promising finds are two rectangular, palm-size bone fragments that appear to have been worked by hand into an object with five pointed teeth on one end. Testing reveals it’s a bear bone, and it is carbon-dated at more than 14,000 years old. It could be the oldest directly dated human-made artifact ever found on American soil—the first tool. But the burden of evidence is high, and Jenkins knows it’s hard to prove these “teeth” were shaped by a human and not by nature. Finding more of the same artifact could help his case. Over the summer, he also found pieces of what he thinks might be fabric, cordage, and basketry; they’re undergoing analysis. If Jenkins’ findings hold, they could cause other details of early U.S. history to be rewritten. Since geologists believe that 14,000 years ago an impassable ice sheet covered northern North America, the “Paisley people” could have come by boat along the Pacific Coast. Also, the first Americans were thought to have mainly eaten large mammals, but the Paisley coprolites reveal that their diet included vegetables, small animals, and bison. Jenkins and his team are digging at Paisley Caves again this summer. “Look, I’m not some great archaeological mind,” he tells me. “I’m just a dirt archaeologist, a worker. I reached this point by being steady.” But now that he’s found a few artifacts, he grins, “Maybe I won’t have to be Dr. Poop too much longer.” --

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