North America's ancient settlement linked to more than one migration
For fans of Jared Diamond books, there's an intriguing article on the Nature journal website about migration patterns into the western hemisphere.
"Samples of fossilized faeces from caves in Oregon show that two distinct tool-making cultures lived side by side more than 13,000 years ago," writes Ewen Calloway. "And a genetic analysis of living Native Americans from dozens of cultures indicates that, in prehistory, North and South America were settled by at least three waves of migrants from Asia."
Traditionally, it was believed that the Clovis people were the first Americans, having travelled across what was then the Bering land bridge into North America.
Now, Calloway reports, stone artifacts in caves and DNA and carbon taken from fossilized feces indicate there was another group that lived on the continent at the same time as the Clovis.
University of Oregon archaeologist Dennis Jenkins told Nature that samples from the Paisley Caves in Oregon demonstrate this.
Meanwhile, Harvard Medical School population geneticist David Reich said that Native Americans moved rapidly down the continent. In addition, there is evidence that there were two later migrations across the Bering land bridge, which gave rise to the Inuit in Greenland and the Chipewyan in northern Canada.
Because they may have interbred with descendants of the earlier arrivals, according to Reich's comments to Nature, archaeologists may have mistakenly believed that all the aboriginal people in North America traced their roots back to a single migration.
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