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8 The Columbia Press August 14, 2020 Hemisphere’s earliest people lived in Oregon By Kristin Strommer Museum of Natural and Culture History In 2017, an international team of researchers joined archaeologist Dennis Jenkins at Oregon’s Paisley Caves. Their aim? To re-examine the site’s sediment and cop- rolites, a nice way of saying ancient fecal remains, in hopes of resolving a long- standing debate about when people first arrived in North America. Results of their study, pub- lished last month in “Science Advances,” confirm Jenkins’ earlier finding that people were living at the site a thou- sand years before the appear- ance of the Clovis people, long thought to be the conti- nent’s first. That culture was named for the distinctive spear points first discovered near Clovis, N.M. Paisley Caves is a system of caves in southcentral Ore- gon. Scientific excavations at the site began in 2002. Jenkins, a senior archae- ologist at the University of Oregon’s Museum of Natu- ral and Cultural History, first discovered the coprolites two decades ago. Since then, ra- diocarbon dating has firmly established their antiquity, with some specimens dating back 14,400 years. Further examination by University of Copenhagen geneticist Eske Willerslev revealed that the coprolites were human based on the mi- tochondrial DNA they con- tain. Still, questions about the coprolites remained, with researchers from Boston to Milan challenging the speci- mens’ human attribution. “Critics pointed to the fact that DNA can be mobile in sediment,” Jenkins said. “So, theoretically, some of the DNA present in the copro- lites could have been the re- sult of contamination from Left: Dennis Jenkins inside Paisley Cave. Courtesy UO Below: A BLM archaeologist outside Paisley Five Mile Cave outside the tow of Paisley. Courtesy BLM overlying layers.” The new study was a direct response to these questions. It zeroed in on fecal lipids, or- ganic substances such as bile acids and sterols that are far less likely than DNA to move around in sediment and can reliably identify the species of the organism that produced a particular poop. The study was co-authored by University of Newcastle archaeologists Lisa-Marie Shillito and John Blong along with Jenkins, UO archaeolo- gist Tom Connolly and Uni- versity of Bristol chemists Helen Whelton and Ian Bull. The researchers analyzed the lipids found in 21 sam- ples taken from the Paisley Caves coprolites. All 21 had been identified as human through earlier analysis, and all but two had previously been radiocarbon dated. The analysis confirmed that three of six coprolites identified as human by mitochondrial DNA were, in fact, of human origin. “The study demonstrates that while there probably was some degree of DNA move- ment from younger human occupations into older sed- iments, people were indeed living at Paisley Caves as much as 14,200 years ago,” Jenkins said. To further confirm the age of one of the coprolites, the authors also radiocarbon dated a bulrush fiber artifact, likely a fragment of a basket or mat, found in the cave sed- iment. “The fragment was dated to roughly 14,000 years before present, giving us a direct ra- diocarbon age on a pre-Clovis cultural artifact and confirm- ing the stratigraphic integ- rity of the cave sediment,” said Connolly, director of ar- chaeological research at the Museum of Natural and Cul- tural History and an expert in the fiber artifacts of the northern Great Basin. Together, the results con- firm that the Paisley copro- lites are the oldest directly dated human remains in the Western Hemisphere. The study is an example of how the dialogue of science operates, Connolly said. “Our understanding is driv- en forward by skepticism,” he said. “When some ques- tioned the attribution of hu- man to the coprolites, DNA studies confirmed the source. When some questioned the accuracy of the DNA find- ings, scientists pursued novel approaches to confirm them. When multiple studies point to the same result, we gain much greater confidence in our findings.”