Grazing sheep along the Karakoram Highway, Xinjiang Province, Silk Road, China (photo credit: ILRI/CAAS-ILRI Joint Laboratory on Livestock and Forage Genetic Resources, Beijing/Han Jianlin).

Waves of domesticated sheep were taken east to China and Mongolia,
with some breeds later brought back

‘Archaeologists have long known that people started to domesticate animals for food at the dawn of agriculture in the Fertile Crescent (the curve of land across the Middle East from the Mediterranean to the Persian Gulf) about 10,000 years ago. But details of the complex pathways through which improved livestock spread across Europe and Asia are only now emerging, as genomic technology makes it practical to compare the DNA of hundreds of animals across continents. . . .

‘A Chinese consortium led the sheep study in collaboration with the International Livestock Research Institute in Nairobi; it is published in the journal Molecular Biology and Evolution.

What we found is that sheep in Asia are far more genetically diverse than sheep now common in Europe—Jian-Lin Han of the Chinese Academy of Agricultural Sciences.

‘The rich genetic heritage of Asian sheep results from two distinct waves of animals driven east from the Fertile Crescent between 7,000 and 5,000 years ago, rather than one wave as previously believed.

Herders in northern China and Mongolia then developed their own breeds,
which later returned to western Asia along the Silk Road.

Genghis Khan’s “Mongol hordes” sometimes rode west
with live sheep strapped to their horses, says Han.

‘Trading of ewes mixed them with progeny of their ancestors to produce further distinct breeds.

‘“This shows that the genetic lineages of modern sheep were shaped by thousands of years of trading and breeding, moving first west to east and then back east to west, which created a unique collection of beneficial traits,” says Olivier Hanotte, a livestock geneticist at the University of Nottingham. . . .

‘Historical information is important for contemporary livestock breeding, [Olivier Hanotte, of the University of Nottingham] adds.

“In the world of animal husbandry, to get what you want
you first need to know what you have.”

Read the whole article at the Financial Times Magazine (subscription required), Animal genomics: Sheep—A very long yarn, 4 Sep 2015.

Read a news release about this work on the ILRI News Blog:
New DNA analysis of Asian sheep reveals unique diversity crucial to contemporary food and climate concerns, 1 Sep 2015.

Read the scientific paper in Molecular Biology and Evolution: Mitogenomic meta-analysis identifies two phases of migration in the history of eastern Eurasian sheep, by Feng-Hua Lv, Wei-Feng Peng, Ji Yang, Yong-Xin Zhao, Wen-Rong Li, Ming-Jun Liu, Yue-Hui Ma, Qian-Jun Zhao, Guang-Li Yang, Feng Wang, Jin-Quan Li, Yong-Gang Liu, Zhi-Qiang Shen, Sheng-Guo Zhao, EEr Hehua, Neena A. Gorkhali, S. M. Farhad Vahidi, Muhammad Muladno, Arifa N. Naqvi, Jonna Tabell, Terhi Iso-Touru, Michael W. Bruford, Juha Kantanen, Jian-Lin Han (ILRI/JLLFGR) and Meng-Hua Li.

This research is conducted at the CAAS-ILRI Joint Laboratory for Livestock and Forage Genetic Resources, within the CAAS Institute of Animal Sciences, in Beijing, China. It is conducted under ILRI’s Animal Biosciences program and within the multi-institutional CGIAR Research Program on Livestock and Fish.