April 4, 2008
DNA Found in Oregon Rewrites the Book on the First Native Americans
By Steve Connor Science Editor
Textbook accounts of how the Americas were first populated may have to be re-written after the discovery in Oregon of the oldest human DNA ever recorded.
The DNA dates from 14,300 years ago - about 1,200 years before the oldest human artifacts produced by the Clovis people, who were thought to be the first inhabitants of North America.
The Oregon find suggests that the Clovis people were preceded by cultures who lived along the west coast of North America when much of the continent was still in the grip of an ice age.
"The data suggests that the Clovis-first hypothesis is dead," said Eske Willerslev, director of the Centre for Ancient Genetics at the University of Copenhagen.
The DNA was extracted from coprolites - fossilised faeces - found in caves near the town of Paisley. It contains two sets of genetic sequences that are shared with modern-day native Americans and people who are native to east Asia and Siberia - confirming that the first Americans came over the Bering land bridge from Asia during the last Ice Age.
Dennis Jenkins, a senior archaeologist at the University of Oregon, said that a lack of bones dating from the time of the Clovis people makes extracting human DNA from coprolites critical to understanding more about the first Americans.
The bones of animals were found in the caves, Dr Jenkins said. "We found a little pit in the bottom of a cave. It was full of camel, horse and mountain sheep bones, and in there we found human coprolite. We radiocarbon-dated the camel and sheep bones, and the coprolite, to 14,300 years ago."
The study, published in the journal Science, went to extraordinary lengths to discount the possibility that the DNA was the result of modern contamination. The DNA of nearly 70 scientists, archaeologists and students was checked to make sure that it had not contaminated the fossilised material.
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