They found evidence that yaks were domesticated 2,500 years ago

European press

La Jornada newspaper
Friday, December 15, 2023, p. 6

Madrid. Archaeological and genetically confirmed evidence of domestic yaks found in Tibet, dating back 2,500 years, is the oldest known record ever.

An international team of researchers zeroed in on that history using ancient DNA from a male yak that lived alongside local cattle and yak-cattle hybrids in a settlement known as Panga, a community on the southern Tibetan plateau about 3,750 meters above sea level. . sea ​​level.

Many scholars have speculated that the yak was first domesticated in the highlands of the Tibetan Plateau.Xinyi Liu, associate professor of archeology in Arts & Sciences at the University of Washington, explained in a statement. It was educated speculation, but so far there is no solid evidence for thishe added. This is the first evidence supported by both archaeology and ancient DNA.

The wild yak, which was once widespread on the Tibetan Plateau, is now listed as exhibition According to the International Union for Conservation of Nature, it is estimated that only 7,500 to 10,000 mature individuals remain in the wild.

However, domesticated ones prevail in many parts of the world. It is estimated that between 14 and 15 million people live in the highlands of Asia alone.

Scientists have traced the origins of other domestic cattle species found in Asia. This includes bullfighting cattle, which are found mainly in Europe and temperate regions of Asia; The indicino, or zebu, is found mainly in India and tropical regions of Asia, and the water buffalo in East and Southeast Asia. Yak remains an open investigationLeo said.

The identification of local specimens and hybrids of yak cattle in Banga is not only essential for understanding the origin of this charismatic creature, the yak, but also provides information more generally on the domestication paths of the animals, where gene flow between related populations is increasingly appreciated.And highlighted.

Seeing everyday life

Panga is one of the oldest agricultural and pastoral settlements on the southern Tibetan Plateau and the only site in the region that contains abundant faunal remains that have been systematically excavated over the past decades. This work, led by Hongliang Lu of Sichuan University, has given scientists insight into daily life at extremely high altitudes between 3,000 and 2,000 years ago, providing excellent momentum for improving our knowledge of the ancient region of the Himalayas.

The excavations at Banga also provide a unique opportunity to explore the early history of yaks, cattle and their hybrids. For this study, published in advance science, Liu and his fellow archaeologists collaborated with livestock geneticists. The team used ancient DNA sequencing as well as archaeozoological analyzes and radiocarbon measurements to help answer questions that cannot be resolved by field studies alone. Our research is a good example of the collaborative, interdisciplinary and international nature of 21st century archaeology.Leo said.

Of the more than 10,000 pieces of mammalian bones collected at Panga, Chengwei Zhang, a University of Washington graduate student and now a postdoctoral researcher at Sichuan University, has been able to identify and classify 193 specimens from the genus bos, a group that includes all domestic cattle, zebras and yaks. , as well as their wild ancestors, the aurochs.

The researchers then selected five well-preserved bones from these bos specimens to sequence for a complete genomic pedigree. The sequencing was supervised by Ningbo Chen and Zhaozhao Li, two leading geneticists at Northwest A&F University who specialize in the domestication of these animals.

Genetic tests

Genetic analysis revealed that only one of the ancient bones came from a yak, a male, while the other four were from female bullfighting cattle. Even the latter was a surprise, Liu pointed out, since Panja is located near and within the Himalayas. Of the zebu and the Indian aurochs, which are not found in this community.

Instead, the cattle belonged to the bullfighting breed that had been introduced to the region from Anatolia via the Silk Road and the northern Tibetan Plateau.

Further analysis helped clarify that the male yak bone was in fact a local variant, and not just from a wild specimen killed by hunters and brought to the settlement for food. The researchers also saw evidence of hybridization between the two species.