US:SCIENTISTS MAY have discovered the oldest evidence yet of human habitation in the New World. The finding, based on an analysis of fossilised human excrement, pushes back the date for the earliest humans in North America to about 14,300 years ago.
The fossilised poop was discovered during fieldwork in Oregon state's Paisley Caves and the samples were later analysed for DNA. The find provides new evidence for human occupation of North America perhaps 1,000 years earlier than currently thought.
Details of the work are published this morning in Science Express, the online edition of the journal Science. The caves are located near Paisley, Oregon, on the eastern side of the Cascade mountain range.
The earliest New World remains have long been attributed to what is known as the "Clovis Culture", about 13,000 years ago. Little is known of these people, beyond their distinctive arrow-head "points" and other tools. No Clovis human remains have been found.
The discoveries in Oregon significantly push back the claim for the earliest humans in the New World and the desiccated excrement provides a great deal of evidence. Fossilised excrement, known as "coprolites", is hugely valuable to archaeologists. Aside from telling you what the person ate, coprolites can be radio-carbon-dated and can provide genetic evidence or mitochondrial DNA. This confirms that the coprolite came from a human and gives information about their family tree.
DNA extracted from the Paisley Caves coprolites showed that these humans belonged to two genetic sub-groups of native Americans which arose between 14,000 and 18,000 years ago in Siberia or eastern Asia. "The Paisley Cave material represents to the best of my knowledge the oldest human DNA obtained from the Americas," said Prof Eske Willerslev, of the University of Copenhagen, one of the study's authors.