Thursday, May 31, 2007

Human remains found in a 1,400-year-old Chinese tomb belonged to a man of European origin, DNA evidence shows

Stefan Lovgren:

Chinese scientists who analyzed the DNA of the remains say the man, named Yu Hong, belonged to one of the oldest genetic groups from western Eurasia.

The tomb, in Taiyuan in central China, marks the easternmost spot where the ancient European lineage has been found (see China map).

"The [genetic group] to which Yu Hong belongs is the first west Eurasian special lineage that has been found in the central part of ancient China," said Zhou Hui, head of the DNA laboratory of the College of Life Science at Jilin University in Changchun, China.

Hui led the research, which will be published in the July 7 issue of the Proceedings of the Royal Society B.

The tomb containing Yu Hong's remains has been undergoing excavation since 1999.

It also contains the remains of a woman of East Asian descent.

The burial style and multicolor reliefs found in the tomb are characteristic of Central Asia at the time, experts say.

The people pictured in the reliefs, however, have European traits, such as straight noses and deep-set eyes.

"The mixture of different cultures made it difficult to confirm the origin of this couple, and the anthropologists also could not determine the race of these remains, owing to the partial missing skulls," Hui said.

To learn more about the history of the couple, Hui's team studied their mitochondrial DNA, a type of DNA inherited exclusively from the mother that can be analyzed to track human evolution.

The research shows that Yu Hong arrived in Taiyuan approximately 1,400 years ago and most probably married a local woman.

Carvings found in the tomb depict scenes from his life, showing him to have been a chieftain of the Central Asian people who had settled in China during the Sui dynasty (A.D. 580 to 618).

The carvings suggest that his grandfather and father lived in northwest China's Xinjiang region and were nobles of the Yu country for which he is named.

Yu Hong died in A.D. 592, at the age of 59. His wife, who died in A.D. 598, was buried in the same grave.

Scientists are using DNA to reconstruct ancient population movements in Asia and to determine when Europeans arrived there.

"The existence of European lineages in China was already known to us, but these lineages are mainly concentrated in Xinjiang province," Hui said.

"In the central part of China, west-Eurasian lineages are seldom found in modern populations and have never been found in an ancient individual."

Austin Hughes is an expert in molecular evolution at the University of South Carolina.

The discovery in China, he said, "shows that there has always been gene flow between human populations."

"I think it's possible that these types of genetic studies can give a clearer picture of human movements and human gene flow," Hughes added.

The DNA studies can also shed light on marriage patterns, said Frederika Kaestle of the Indiana Molecular Biology Institute at Indiana University in Bloomington.

"In many cases there are no other methods that allow us to gain access to information on geographic origin or relatedness of individuals in archaeological contexts," Kaestle said.

However, she added, it is impossible to draw conclusions about population movement into the region based on this one DNA sample.

"Was it just this one man [who moved into the area], or was it a large family including this man, or was it an even larger group of people from his ancestral population?" she asked.

Overall, she said, "the study of ancient mitochondrial DNA, as well as other genomic variations, holds great promise for enhancing our understanding of human prehistory."

"This is a nice example of how genetic and archaeological approaches can be combined fruitfully."

Caucasians preceded East Asians in basin

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