On October 28, Beijing time, Nature News headlines published an article titled "DNA reveals surprise ancestry of mysterious Chinese mummies".
In the 1990s, hundreds of naturally preserved mysterious mummies unearthed in China's Tarim Basin attracted the attention of the international archaeological field, but their identities remain a mystery to this day. Some scholars believe that these Bronze Age remains were immigrants from thousands of kilometers west who brought farming methods to the area. But now, a genomic analysis suggests that they are local indigenous peoples who may have learned the agricultural methods of neighboring groups in some way.
In the new study, published in Nature on October 27, 2021, researchers from Professor Cui Yinqiu of the School of Life Sciences of Jilin University, together with the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, Seoul National University in South Korea, Harvard University in the United States, and the Max Planck Institute in Germany, traced the ancestors of early Chinese farmers to Stone Age hunter-gatherers living in Asia about 9,000 years ago, and they appear to be genetically independent. Nevertheless, they learned to raise livestock and grow grain in the same way as other groups.
Christina Warinner, a molecular archaeologist at Harvard University and co-corresponding author of the study, said: "This study hints at differences in the way humans migrate and how ideas spread with population. ”
Michael Frachetti, an archaeologist at Washington University in St. Louis, said the finding suggests that cultural exchange does not always go hand in hand with genetic relationships. These people are just interacting with each other, but this does not necessarily mean getting married and having children.
Perfect storage environment
Beginning in the early 20th century, these mummies were found in cemeteries belonging to the so-called Xiaohe culture, scattered throughout the Taklamakan Desert in China's Xinjiang region.
Alison Betts, an archaeologist at the University of Sydney in Australia, said: "Deserts are one of the worst places on earth. There, the bodies were buried in ship-shaped coffins wrapped in cowhide. The hot, arid and salty environment of the desert naturally preserves them. So everything from their hair to their clothes is intact. Before this latest study, we knew enough about the physical condition of these people, but we didn't know who they were or why they were there. ”
She added that the mummies, which have been buried for more than 2,000 years, can be traced back to an important period in Xinjiang's history, when ancient communities were transforming from hunter-gatherers to farmers.
Some later mummies are buried in woolen fabrics and garments similar to those of Western culture. Also in the grave are millet, wheat, animal bones and dairy products. This is evidence of agricultural and livestock techniques specific to the rest of Eurasia. This led previous research to assume that these people had originally migrated from the west, passing through Siberia, Afghanistan or Central Asia.
In this latest study, researchers extracted DNA from mummies to try to validate these ideas, but they found no evidence to support them.
They sequenced the genomes of 13 people who lived between 4100 and 3700 years ago, the mummies found at the bottom of the cemetery in the Tarim Basin in southern Xinjiang, and 5 mummies from hundreds of kilometers north of Xinjiang, who lived between 5,000 and 4,800 years ago.
The researchers then compared the genetic profiles of these mummies with genomes previously sequenced from more than 100 ancient and more than 200 modern populations around the world.
Two groups
They found that these mummies in northern Xinjiang shared part of their genome with Bronze Age immigrants from the Central Asian Altai Mountains who lived about 5,000 years ago, supporting earlier assumptions.
However, the 13 mummies from the Tarim Basin do not share a common ancestor.
Choongwon Jeong, a population and evolutionary geneticist at Seoul National University and co-corresponding author of the study, said they appear to be only associated with hunter-gatherers who lived in southern Siberia and now northern Kazakhstan about 9,000 years ago. Individuals in northern Xinjiang also have some such ancestry.
Because evidence of dairy products was found next to the youngest mummy in the upper layer of the Tarim Basin cemetery, the researchers analyzed calcified plaques on the teeth of some older mummies to understand the history of dairy farming. In the plaques, they found milk protein from cattle, sheep and goats, suggesting that even the earliest settlers here consumed dairy products
Warinner said: "These founders have integrated dairy livestock into their lives. ”
But Betts said: "This study raises more questions about how people in the Creek culture got these technologies, where did they come from and from whom?" This is the next problem we need to try to solve. ”
https://www.nature.com/articles/d41586-021-02948-y
https://www.nature.com/articles/s41586-021-04052-7
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