Decades ago, researchers discovered hundreds of naturally mummified bodies buried in boats in a barren desert in northwest China. Dated to as long as 4,000 years ago, the mummies’ clothing and burial goods led some scholars to posit that they were migrants from West Asia. But new DNA evidence published in the journal Nature suggests the so-called Tarim mummies actually descended directly from a population that lived in the region during the Ice Age.
“We found strong evidence that they actually represent a highly genetically isolated local population,” study co-author Christina Warinner, an anthropologist at Harvard University, tells CNN’s Katie Hunt.
Known as Ancient North Eurasians (ANE), the distinct group spread across a large area during the Ice Age but had mostly disappeared by around 10,000 years ago. Scientists have found small traces of their genetic lineage in present-day people, particularly Indigenous populations in Siberia and North America.
“Archaeogeneticists have long searched for Holocene ANE populations in order to better understand the genetic history of Inner Eurasia,” says co-author Choongwon Jeong, a geneticist at Seoul National University, in a statement from the Max Planck Institute for Evolutionary Anthropology. “We have found one in the most unexpected place.”
The human remains, found in multiple cemeteries in the Xinjiang Uyghur Autonomous Region’s Tarim Basin, were buried over a long period, from approximately 2000 B.C.E. to 200 C.E, reports Isaac Schultz for Gizmodo. They were first discovered in the early 20th century, with the majority of excavations completed in the 1990s. The 13 Tarim mummies whose DNA researchers sequenced for the new study are among the group’s oldest, dating to between 4,100 and 3,700 years ago, Nature News’ Smriti Mallapaty writes.
Thanks to the basin’s dry conditions, the mummies were remarkably well preserved, often with their hair and clothing still intact. Their culture appears to have been distinctive. Despite living in a desert area, they were buried in boat-shaped structures covered in cowhides with grave markers shaped like oars—a practice most often associated with the Vikings.
“They bury their bodies in boats, and no one else does that,” Michael Frachetti, an anthropologist at Washington University in St. Louis who wasn’t involved in the study, tells CNN. “That means where that tradition comes from remains one of the biggest enigmas of this desert population, which should be the last community in the world to do this.”
Previous excavations at archaeological sites in Tarim have yielded ancient nets likely used for fishing in rivers that ran through the desert, reports Tom Metcalfe for Live Science. Warinner says the boats may have acted as a tribute to the importance of these rivers, which created oasis environments conducive to survival in an inhospitable climate.
The mummies’ clothing—made out of wool, felt and leather—were unusual for the region. Some of the deceased appear to have red or light-colored hair and facial features unusual in Asian populations. And a number of the more recent mummies were buried with pieces of cheese around their necks, perhaps intended as food for the afterlife. Together, these factors led some archaeologists to hypothesize that the enigmatic individuals were migrants from southern Siberia or the Central Asian mountains.
The new study compares the Tarim mummies to similarly ancient human remains found in China’s Dzungaria region, on the other side of the Tianshan mountain range. The Dzugarian people descended from both ANE and Afanasievo herders from southern Siberia, while the Tarim people remained more genetically isolated.
“We speculate that the harsh environment of the Tarim Basin may have formed a barrier to gene flow, but we cannot be certain on this point at the moment,” Jeong tells Live Science.
The Tarim people apparently did mix culturally with their neighbors, adopting such practices as herding cattle, goats and sheep, as well as farming wheat, barley and millet.
“Despite being genetically isolated, the Bronze Age peoples of the Tarim Basin were remarkably culturally cosmopolitan,” says Warinner in the statement.
The mummies’ teeth showed evidence of proteins from dairy products, indicating that their civilization’s adoption of herding began early.
“This founding population had already incorporated dairy pastoralism into their way of life,” Warinner tells Nature News.