Ancient DNA Reveals History of Mongolia’s First Nomadic Empire

A new study examining ancient DNA has shed new light on the multiethnic structure of Mongolia’s first nomadic empire, the Xiongnu. The research is published in Science Advances.

Revealing Mongolia’s ancient genetic history

Inhabiting the Mongolian steppe in East Asia approximately 1,500 years before the emergence of the Mongols, the Xiongnu were one of the region’s most powerful and formidable forces during the Iron Age. Their economy was mainly rooted in animal husbandry and dairy farming, while their prowess in mounted combat prompted the construction of what would later become part of the Great Wall. Their culture was famously nomadic, with their influence stretching across the continent as far as Egypt and Rome.

However, historical records of the Xiongnu are sparse and provide little information on their origins, political growth or social structure. They had no writing system, meaning historical records referencing the Xiongnu originated from their rivals and enemies, namely chroniclers from China’s Han Dynasty.

Genetic studies of ancient DNA (archeogenetic studies) have revealed some insights into the origins of the Xiongnu, though their findings have ultimately raised more questions than answers. The empire’s political origins have been traced to a sudden migration and mixing of nomadic groups in northern Mongolia around the year 200 BCE, before the empire disintegrated in the late 1^st century CE.

Now, an international team of researchers has conducted painstaking archeological excavations to unearth new evidence from ancient DNA. Samples were taken from two cemeteries for “elite” members of Xiongnu society found along the empire’s western frontier. The international collaboration included researchers from the Max Planck Institutes for Evolutionary Anthropology and Geoanthropology, Seoul National University, the University of Michigan and Harvard University.

“We knew that the Xiongnu had a high degree of genetic diversity, but due to a lack of community-scale genomic data it remained unclear whether this diversity emerged from a heterogeneous patchwork of locally homogenous communities or whether local communities were themselves genetically diverse,” explained Juhyeon Lee, first author of the study and PhD student at Seoul National University. “We wanted to know how such genetic diversity was structured at different social and political scales, as well as in relation to power, wealth and gender.”

Insights into the Xiongnu empire

DNA from individuals analyzed in this study indicated that they were highly genetically diverse, a trait likely shared by the whole empire. This confirms the Xiongnu as a multiethnic population, with high diversity and heterogeneity within individual communities and families.

However, the researchers also found that levels of diversity differed according to individuals’ social status. Low-status individuals, likely servants as they were interred as satellite burials of the elites, displayed the highest level of genetic diversity. These people likely originated from distant regions of the empire and beyond. On the other hand, the elites (indicated by their elaborate burial sites and tombs) exhibited lower levels of diversity, with a high proportion of eastern Eurasian ancestry. The findings also suggest that such elite families used marriage to strengthen connections to newly incorporated groups.

Excavation of the Xiongnu Elite Tomb 64 containing a high status aristocratic woman at the site of Takhiltiin Khotgor, Mongolian Altai. Credit: J. Bayarsaikhan

“We now have a better idea of how the Xiongnu expanded their empire by incorporating disparate groups and leveraging marriage and kinship into empire building,” said Dr. Choongwon Jeong, senior author of the study and associate professor of biological sciences at Seoul National University.

Long-standing traditions

Evidence from burial sites suggested that women played a prominent role in political society, as high-status burials and “elite grave goods” – such as Chinese mirrors, silk clothing and objects conventionally associated with male horse-mounted warriors – were strongly associated with women. Their tombs were heavy with symbolism, including elaborate emblems of imperial power, and were often flanked by low-status males with simple burials. Strikingly, one tomb even contained a team of six horses and a partial chariot.

The roles of children were also explored through genetic analysis, with findings suggesting that gendered roles, like hunters and warriors, were not assigned to boys until they reached adolescence. The researchers noted that adolescent boys were buried with similar items to young men, such as bows and arrows, though younger boys were not. Dr. Christina Warriner, senior author of the study and associate professor of anthropology at Harvard University, explained: “Children received differential mortuary treatment depending upon age and sex, giving clues to the ages at which gender and status were ascribed in Xiongnu society.”

Overall, the results of the genetic study shed light on the long-lasting social and cultural traditions of the Xiongnu. “Our results confirm the long-standing nomadic tradition of elite princesses playing critical roles in the political and economic life of the empires, especially in periphery regions – a tradition that began with the Xiongnu and continued more than a thousand years later under the Mongol Empire,” said Dr. Jamsranjav Bayarsaikhan, study co-author, postdoctoral researcher and project coordinator at the Max Planck Institute for Geoanthropology. “While history has at times dismissed nomadic empires as fragile and short, their strong traditions have never been broken.”

Reference: Lee J, Miller BK, Bayarsaikhan J, et al. Genetic population structure of the Xiongnu Empire at imperial and local scales. Sci Adv. 2023. doi: 10.1126/sciadv.adf3904 

This article is a rework of a press release issued by the Max Planck Society. Material has been edited for length and content.