Just off the Silk Road, in the deserts of China's Xinjiang Uyghur Autonomous Region, there lies hundreds of human remains naturally preserved by the dry desert air. Known as the Tarim Basin mummies, they have now been genetically studied, with scientists discovering a surprising origin, helping to explain how this population picked up their unusual traditions and appearances that have long-baffled researchers.

Dating from 2,000 BCE to 200 CE, the mummies have gathered a fair amount of curiosity since they do not resemble the other ancient inhabitants of the region. Instead, they have comparatively “Western” features, wore colorful woolen clothing, and were buried alongside other signs of a farming culture that included cattle, sheep and goat, wheat, barley, millet, and cheese. Perhaps strangest of all, the Tarim Basin mummies were buried in a barren desert in boat-shaped coffins covered in cow hides. 

In a new study, published in the journal Nature, researchers used genetic analysis to study thirteen of the earliest known Tarim Basin mummies, dating to circa 2,100 to 1,700 BCE. This revealed that they were the direct descents of the Ancient North Eurasians (ANE), a local population of hunter-gatherers who inhabited the north Eurasian steppe and Siberia. This once widespread group disappeared around 10,000 years ago, but their genetic footprint can still be found in present-day populations of Indigenous populations in Siberia and the Americas. 

While not all of the unique cultural relics of the Tarim Basin mummies appear naturally suited to their surrounding environment – boat burials and wool aren’t typically associated with deserts – the new analysis suggests that this population of people were not newcomers to the area and had an overwhelmingly local ancestry. This stands in stark contrast to previous theories, which speculated the herders from the Black Sea region of southern Russia, Central Asians, or early farmers on the Iranian Plateau. 

“Despite being genetically isolated, the Bronze Age peoples of the Tarim Basin were remarkably culturally cosmopolitan – they built their cuisine around wheat and dairy from the West Asia, millet from East Asia, and medicinal plants like Ephedra from Central Asia,” Christina Warinner, a senior author of the study, professor of Anthropology at Harvard University, and research group leader at the Max Planck Institute for Evolutionary Anthropology, said in a statement

It also appears that they did not mix much with other nearby populations, instead forming a previously unknown genetic isolate that likely underwent an extreme genetic bottleneck before arriving in the area. This is pretty surprising considering other populations were widely intermingling in Tarim Basin throughout this time. 

Digging deeper into this enigmatic population, the team also analyzed the genetics of five human remains dating to circa 3,000 to 2,800 BCE in the neighboring Dzungarian Basin. This showed a totally different story – the mummies of Dzungarian were descended from both local populations plus herders from the Western steppe herders who have strong genetic links to the Early Bronze Age Yamanya.

Altogether, the findings further highlight how this unlikely place played a truly unique role in the Bronze Age cultures of Eurasia, acting as a vital crossroads between East, West, North, and South. 

“Reconstructing the origins of the Tarim Basin mummies has had a transformative effect on our understanding of the region, and 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,” adds Yinquiu Cui, a senior author of the study and professor in the School of Life Sciences at Jilin University in China.