DNA from Fossil Feces Breaks Clovis Barrier

NEWS OF THE WEEK ARCHAEOLOGY DNA From Fossil Feces Breaks Clovis Barrier Who were the first Americans? A decade ago, cans—and not shared by any other population dogs, coyotes, or wolves—or canids may have most archaeologists bestowed this distinction groups—from six of the coprolites. urinated on the human feces. But if these were upon the so-called Clovis people, who left ele- Because the coprolites were not exca- actually canid rather than human coprolites, gantly fluted projectile blades across the vated under sterile conditions, the team was some researchers say, it might be the other United States and Central America beginning not surprised to find modern mtDNA con- way around: The DNA could be from the about 13,000 years ago. But since the late tamination from people of European origin. urine of humans who ventured into the caves 1990s, evidence for an earlier peopling of the To ensure that the Native American DNA long after the coprolites were deposited. “The Americas has steadily accumulated. was not from similar contamination, coprolites are the same size and shape as both Now, in a Science paper published online researchers analyzed the mtDNA of all human and canid feces, and less than half of (www.sciencemag.org/cgi/content/abstract/ 55 people present at the dig, plus all 12 scientists the [14] coprolites had human DNA in them,” 1154116) this week, an international team at the Copenhagen lab. None had the Native notes anthropologist Gary Haynes of the Uni- reports what some experts con- versity of Nevada, Reno. sider the strongest evidence yet Team members reject this explanation against the “Clovis First” posi- and offer yet more data as evidence: They tion: 14,000-year-old ancient tested for and found human proteins in three DNA from fossilized human coprolites, including two dated to about excrement (coprolites), found 14,000 years ago. “This nongenetic test in caves in south-central Ore- requires more human protein than can be gon. “This is the smoking gun” expected from urination,” explains Willerslev. for an earlier colonization of Jenkins adds that human hair was found in on April 8, 2008 the Americas, says molecular the coprolites too. “Whether the coprolites anthropologist Ripan Malhi of are human or canine is irrelevant, since for a the University of Illinois, canine to swallow human hair people had to Urbana-Champaign. The new be present in that environment,” he says. work, combined with recent “People eat canines, canines eat people, and finds at even earlier sites in canines eat human feces. Florida, Wisconsin, and else- Any way you cut the where (Science, 14 March, Prehistoric poop. Coprolites from Oregon’s poop, people and dogs p. 1497), “add up to a human Paisley Caves (inset) push back dates for the would have to be at the www.sciencemag.org presence on the continent by first Americans. site within days of each 15,000 years ago,” says geoar- other 14,000 years ago.” chaeologist Michael Waters of Texas A&M American signatures. Such an early date University in College Station. (All dates are Next, the team called in nixes any claims of Clo- given in calibrated calendar years.) two other well-known vis priority, because But some members of both camps cau- ancient DNA labs, which demographic studies tion that the team has not entirely ruled out each independently veri- have shown that early Downloaded from the possibility of modern contamination— fied the findings. Finally, colonizers could have or that the feces were left by dogs rather two leading labs radio- fanned out across the than people. There is “an element of doubt,” carbon-dated the coprolites and found that at United States in as little as 100 years. “The says anthropologist Thomas Dillehay of least three were 14,000 years or older. Clovis First argument is pretty much dead in Vanderbilt University in Nashville, Ten- “This is an excellent paper that will set the the water,” says archaeologist Jon Erlandson nessee, whose excavations at a 14,600-year- agenda for future research,” says ancient of the University of Oregon, Eugene. “But old Chilean site also challenge the Clovis DNA researcher Terry Brown of the Univer- our knowledge of what came before is still First paradigm. sity of Manchester, U.K. “I am convinced that very sparse.” The 14 coprolites were found in 2002 and the [human] DNA they detected is not mod- Erlandson, Waters, and others say the 2003 during excavations in Oregon’s Paisley ern contamination.” Adds anthropologist coprolite data bolster the idea that when the Caves, led by archaeologist Dennis Jenkins of David Smith of the University of California, first Americans came east from Asia, they the University of Oregon, Eugene. From the Davis: “If this doesn’t convince what’s left of arrived on the Pacific Coast rather than taking size, shape, and color of the coprolites, Jenkins’s the Clovis First people, it should.” an inland route. At 14,000 years ago, ice sheets team concluded that they had been produced However, Brown, along with leading pre- would have mostly blocked the inland path. by humans. The researchers then joined up Clovis skeptics such as Stuart Fiedel of the The coastal theory is attractive to many, but with ancient DNA specialists Eske Willerslev Louis Berger Group in Washington, D.C., archaeological details have been scarce. Says and Thomas Gilbert of the University of says that the coprolites do not make an airtight Jenkins: “We may not know much about the Copenhagen in Denmark (Science, 6 July case for pre-Clovis occupation. That’s first Americans, but if we are going to search 2007, p. 36). The pair succeeded in extracting because the team also reported finding canid for [them], we need to be working beyond the human mitochondrial DNA (mtDNA) with DNA in three coprolites. The co-authors sug- 13,000-year Clovis barrier.” CREDITS: DENNIS L. JENKINS genetic signatures typical of Native Ameri- gest that humans might have eaten canids— –MICHAEL BALTER www.sciencemag.org SCIENCE VOL 320 4 APRIL 2008 37 Published by AAAS.

Load more