XINJIANG DISCOVERY PROVIDES INTRIGUING DNA LINK
The DNA of some 4,000 year-old bodies unearthed five years ago in Xinjiang, in northwest China, provides scientific evidence of early intermingling between people of European and Asian origin.
Zhou Hui, a professor of life science and her team discovered that some of the earliest inhabitants of the Tarim Basin in the Taklamakan Desert were of European and Siberian descent.
The basin, where hundreds of well-preserved mummies have been found since the 1980s, has attracted great attention from scientists worldwide.
Professor Victor Mair of Pennsylvania University claimed in 2006, "From around 1800 B.C. the earliest mummies in the Tarim Basin were exclusively Caucasoid, or Europoid," after he studied DNA samples derived from five bodies unearthed in the basin.
However, Professor Jin Li of Shanghai-based Fudan University, announced in 2007 that the mummies' DNA in the basin's Loulan area, including the 3,800-year-old Loulan Beauty, indicated East Asian, even South Asian origin.
Many archaeologists have accepted that people living in the basin as early as 3,800 years ago, or the Bronze Age, were of European descent, with Asians, mainly from east Asia, only arriving during the Iron Age, Zhou said. "But when the population from Europe and Asia began 'intermarrying' in the area still remains a mystery," she added.
Zhou and her team got DNA samples from the bones and teeth of 20 mummies, around 4,000-year-old. They were all excavated at the Xiaohe cemetery in the basin in 2004 and 2005.
The analyzed DNA profiles included the mitochondrial DNA, which is exclusively passed down through the mother, and the Y chromosome, passed down from father to son.
We found that DNA from five of the seven males derived from their mother, belonged to a lineage that came from Siberia, most likely from south or eastern Siberia, while their Y chromosome indicated European ancestry, Li Chunxiang, another researcher with the team, told Xinhua.
The seven males' Y chromosome had similarities to ancient Europeans who wandered the Eurasian Steppe, stretching roughly 3,000 miles from west to east, mainly in Central Asia.
People of the lineage can be found now in Eastern Europe, Central Asia and Siberia, but rarely in East Asia, Li said.
The mitochondrial DNA of five males and the nine other mummies (four females and five mummies whose gender is unknown) indicated they were related to an ancient lineage that can now be found mostly in modern Siberia, East Asia and Central Asia, Li said.
Their maternal lineage could be traced to Asian populations most likely lived in south Siberia, she said.
Two other females' DNA indicated their maternal ancestors had come from Western Europe.
"Our finding show the European and Siberian tribes began socializing with each other, even intermarrying, almost 4,000 years ago," Zhou said.
But scholars said the Europeans and Siberians might have met and intermarried outside the basin before their immigration into the basin.
"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.