"The civilization of the Tarim Basin, according to archaeological findings, arose very late. The 4,000-year-old mummies we found in Xiaohe are believed to be among the earliest inhabitants in the basin. But the Xiaohe people's DNA lineages are over 10,000 years old," Li said.

DNA with both European and Asian markings was also found in south Siberia. People of European origin had spread eastward into that region during the Bronze Age, she said.

The Xiaohe cemetery, 175 km west of the ancient city of Loulan, is located on the ancient Silk Road, once a booming trade route traversing the Asian continent.

The burial ground, with 167 graves, was first explored by Folke Bergman, a Swedish archaeologist in 1934. But it "vanished" until the Xinjiang Archaeological Institute rediscovered it in 2000, Zhou said.

The excavation of the cemetery began in 2002, but only experts with the institute and the Research Center for Chinese Frontier Archaeology of Jilin University were authorized to unearth the lowest layer where the oldest mummies were buried.

"We found 41 graves in this layer, and 37 of them had human remains. The corpses were lying in bottom-up-boat-like coffins. They all had distinctive European appearances and were well-preserved thanks to the dry air and good drainage." She said.

Some mummies unearthed in the Tarim Basin are displayed in a number of museums in Xinjiang, said Idelis Abdurisulu, former director with the Institute of Cultural and Historical Relics and Archaeology of Xinjiang Uygur Autonomous Region.

"The regional museum has six or seven mummies, while others are scattered around Xinjiang in some smaller museums," he said.

In late March, the Bowers Museum in Santa Ana in California began exhibiting two of the Tarim Basin mummies, including Xiaohe Beauty, a 3,800-year-old female, and Qiemo Baby, an infant aged eight to 10 months who died about 2,800 years ago.