Oct. 27 (UPI) -- A genomic study of the Tarim Basin mummies in western China has revealed an indigenous Bronze Age population that was genetically isolated but culturally cosmopolitan, researchers said Wednesday in an article published by Nature.
The analysis of genome-wide data from 13 mummies discovered in the region more than 20 years ago found no evidence of genetic mixing with peoples of other populations in the region, the researchers said.
This is contrary to earlier research findings highlighting extensive genetic mixing all around the Tarim Basin throughout the Bronze Age, or roughly 3,300 BCE to 1,200 BCE, they said.
The Tarim Basin population was not culturally isolated, however, as revealed by a proteomic analysis, or assessment of proteins, found in tartar on the surface of their teeth.
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The analysis confirmed that the founding population was practicing cattle, sheep and goat dairying and that they were well aware of the different cultures, cuisines and technologies around them, the researchers said.
"Despite being genetically isolated, the Bronze Age peoples of the Tarim Basin were remarkably culturally cosmopolitan," study co-author Christina Warinner said in a press release.
"They built their cuisine around wheat and dairy from the West Asia, millet from East Asia and medicinal plants like Ephedra from Central Asia," said Warinner, a professor of anthropology at Harvard University.
As part of the Silk Road, the Xinjiang Uyghur Autonomous Region has long served as a major crossroads for trans-Eurasian exchanges of people, cultures and languages, according to the researchers.
The discovery of hundreds of naturally mummified human remains dating from 2,000 BCE to 200 CE in the region's Tarim Basin in the late 1990s, in an area called the Xiaohe cemetery, has attracted international attention due to their "Western" physical appearance.
The mummies' cattle-focused economy and unusual physical appearance led some scholars to speculate that they were descendants of migrating Yamnaya herders, a highly mobile Bronze Age society from the steppes of the Black Sea region of southern Russia.
To better understand the origins of the region's founding population, the researchers generated and analyzed genome-wide data from 13 of the earliest known Tarim Basin mummies, dating from 2,100 to 1,700 BCE.
They combined this information with genome-wide data from five mummies dating from 3,000 to 2,800 BCE in the neighboring Dzungarian Basin.
The results revealed that the Tarim Basin mummies were not newcomers to the region but were instead direct descendants of a once widespread Pleistocene population that had largely disappeared by the end of the last Ice Age, the researchers said.
This population, the Ancient North Eurasians, survives only fractionally in the genomes of present-day populations, with Indigenous populations in Siberia and the Americas having the highest known proportions.
In contrast to populations today, the Tarim Basin mummies show no evidence of genetic admixture with any other Holocene groups, the researchers said.
"[Scientists] have long searched for Holocene Ancient North Eurasian populations in order to better understand the genetic history of Inner Eurasia," co-author Choongwon Jeong said in a press release.
"We have found one in the most unexpected place," said Jeong, a professor of biological sciences at Seoul National University in South Korea.
In contrast to the Tarim Basin, the earliest inhabitants of the neighboring Dzungarian Basin descended not only from local populations but also from Western steppe herders, according to Jeong and his colleagues.
"Reconstructing the origins of the Tarim Basin mummies has had a transformative effect on our understanding of the region," co-author Yinquiu Cui said in a press release.
"We will continue the study of ancient human genomes in other eras to gain a deeper understanding of the human migration history in the Eurasian steppes," said Cui, a professor of life sciences at Jilin University in Changchun, China.
