As a part of the Silk Road, Xinjiang Uygur Autonomous Region is located at the intersection of eastern and western cultures and has long been an important crossroads for people, culture, agriculture and language exchanges in Eurasia. Since the late 1990s, hundreds of human remains of natural mummies, including cattle, sheep and goats, wheat, barley, millet and even Kefir cheese, have been found in the Tarim Basin in this area, because of their so-called "western" appearance, felt and woven wool clothes and their agriculture and animal husbandry economy. Mummies in Tarim Basin were buried in coffins in barren desert, which has always puzzled scientists and inspired many theories about their mysterious origin.
The cattle-centered economy and the unusual appearance of mummies in Tarim Basin have led some scholars to guess that they are descendants of migrating Yanaya herders, a highly mobile bronze age society from the steppes of the Black Sea region in southern Russia. Others put their origins in the Central Asian desert oasis culture of Bactria-Marguillard archaeological complex (BMAC), which is closely related to the early farmers in the Iranian plateau.
In order to better understand the origin of mummies in Tarim Basin, they first settled in Xiaohe and Gumugou around 2000 BC. Max Planck, an international team of researchers from Jilin University, Institute of Vertebrate Paleontology and Paleoanthropology, Seoul National University and Institute of Evolutionary Anthropology of Harvard University, generated and analyzed the 13 genome-wide data of the earliest mummy in Tarim Basin. These mummies can be traced back to 2 100 to 1700 BC, and there are five young mummies dating back to 3000 to 2800 BC in the neighboring Junggar basin. This is the first time that Xinjiang Uygur Autonomous Region has conducted a genome-scale study on prehistoric humans, including the earliest human remains found in this area so far.
Aerial view of Xiaohe cemetery.
Mummies in Tarim basin are not newcomers to this area.
To their great surprise, the researchers found that the mummies in Tarim Basin were not newcomers to the area at all, but seemed to be direct descendants of the once widely distributed Pleistocene population, which had basically disappeared at the end of the last ice age. This population, called the Ancient Norse (ANE), accounts for only a small part of the genome of modern people, among which the indigenous population in Siberia and America has the highest known proportion, about 40%. Compared with today's population, the mummies in Tarim basin showed no evidence of mixing with any other Holocene population, but formed a previously unknown genetic isolation, which may have experienced an extreme and long-term genetic bottleneck before settling in Tarim basin.
"In order to better understand the genetic history within Eurasia, archaeological geneticists have been looking for Holocene ANE population for a long time. We found a population in the most unexpected place, "said Choongwon Jeong, a senior author of the study and a professor of biological sciences at Seoul National University.
M 13 tomb profile of Xiaohe cemetery.
Contrary to the Tarim Basin, the earliest residents near Junggar Basin came not only from the local population, but also from the western grassland herders, namely the Afanasi Wo people, a herdsman group closely related to the Amanya people in the early Bronze Age. The genetic characteristics of Junggar people in the early bronze age also helped to clarify the ancestors of other herders, who were called Chemurchek, and later spread northward to Altai Mountains and into Mongolia. Chemurchek group seems to be descended from Junggar people in the early Bronze Age and Central Asia group from the Inner Asia Mountain Corridor (IAMC), and their ancestors came from local population and BMAC farmers and herdsmen.
"These findings have increased our understanding of the eastward spread of Yanaya lineage and the mixed scenes when they first met Neiya population," said Zhao Ning, a professor at the Institute of Archaeology and co-lead author of the study. Museology in Peking University.
Brief report on excavation of M75 tomb in Xiaohe cemetery.
The Tarim basin group is not so much culturally isolated as genetically isolated.
The discovery of extensive genetic mixing around Tarim basin in the whole Bronze Age makes the evidence that mummies in Tarim basin did not show genetic mixing at all more striking. However, although all ethnic groups in Tarim Basin are genetically isolated, they are not culturally isolated. Protein omics analysis of their dental calculus confirmed that the founders had started to engage in dairy industry of cattle, sheep and goats, and they were very familiar with different cultures, cuisines and technologies around them.
Christina Warriner, a senior author of the study, a professor of anthropology at Harvard University and head of the research group of Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, said: "Although the genes were isolated, the people in the Bronze Age in Tarim Basin were very international in culture-they featured medicinal plants, such as wheat and dairy products in West Asia, millet in East Asia and ephedra in Central Asia."
Typical river boat coffin and paddle. The coffin was covered with cowhide.
"Rebuilding the origin of mummies in Tarim Basin has had a revolutionary impact on our understanding of this area, and we will continue to study the ancient human genomes of other times in order to have a deeper understanding of the history of human migration in Eurasian grasslands," added Cui Yinqiu, a senior author of the study and a professor at the School of Life Sciences of Jilin University.