DNA Analysis Of Ancient Bone Adds Diversity To Native American Origins

DNA analysis of the right arm bone of a 24,000 year old human boy altered present theories of where Native Americans originated from, The New York Times reported. The surprising results revealed the 3 year-old's DNA matched the sequence found among Western Europeans - not Eastern Asians, as previously believed - and shared 25 percent of the DNA found in today's Native Americans. The findings indicate America's first inhabitants originated from both Western Europe and East Asia.

Long-held assumptions almost prevented the discovery from taking place -- and continue to arise as a team of researchers, led by Dr. Eske Willersley, begin to present their findings.

"There was a lot of surprise and some skepticism, as is often the case in science toward new findings," said Dennis H. O'Rourke, an anthropologist at the University of Utah.

When Willerslev of the University of Copenhagen first examined the bone, discovered in Siberia in 1958 but studied in depth only recently, he thought the sample was contaminated because its mitochondrial DNA too closely resembled that of more modern humans, who first traveled to Europe around 44,000 years ago. Willersely figured one of the bone's handlers over the years, presumably of European origin, contaminated it with his or her own DNA.

"The study was put on low speed for about a year because I thought it was all contamination," Willerslev said.

When they looked through the bone's nuclear genome, responsible for a majority of human inheritance, they were shocked to find more evidence connecting it to ancient Europeans. To confirm, they conducted the same analysis on a bone from 17,000 years ago found in the same location and found the same results, The Times reported.

The findings indicate that modern humans spread much further across Eurasia than previously anticipated, according to The Times. Descendants of the Mal'ta culture, of which this boy and his people were part, would continue to live in Siberia during a treacherously cold period called the Last Glacial Maximum, which began 20,000 years ago, according to Willersely. Ice sheets covered much of the planet during this time.

Willersely further theorized that the ancestors of Native Americans (of European descent) had already made their journey to the Americas when members of the Mal'ta culture and East Asian populations interbred and also made their way to the Americas by way of the Siberian land bridge, The Times reported.

"We estimate that 14 to 38 percent of Native American ancestry may originate through gene flow from this ancient population," Willersely and colleagues wrote in their paper, The Times reported.