The team of researchers sequenced the complete mitochondrial DNA of 42 domesticated native sheep breeds from Azerbaijan, Moldova, Serbia, Ukraine, Russia, Kazakhstan, Poland, Finland, China, and the U.K. plus two wild sheep species from Kazakhstan. The genomic data, comprising of thousands of tissue samples, was compared to equivalent data from 150 breeds of sheep from other countries.
The study found that sheep (Ovis aries) found in Asia are considerably more genetically diverse than sheep found in Europe. The findings suggest that the complex genetic heritage of Asian sheep is due to two separate “migratory waves” where the animals underwent domestication. Previous research had suggested just one domestication event.
The first event appears to have occurred when sheep were domesticated in the Fertile Crescent, around 8,000 to 11,000 years ago. Sheep were then moved eastwards to what is now modern day China and Mongolia via the Silk Road trading routes. The ‘Silk Road‘ is a term applied to various routes within the Asian continent connecting the West and East. Along this route merchants, pilgrims, monks, soldiers, nomads, and urban dwellers traversed from China and India to the Mediterranean Sea This event was previously established.
New evidence suggests farmers in areas that are now part of northern China reared their own breeds some 5,000 years ago. These animals ended up intermixing and interbreeding with sheep along the Silk Road, leading to greater species diversification.
The new information informs farmers about current attempts at sheep breeding. It is hoped that the information about sheep diversity in Asia will help herders in certain regions, including Mongolia and western China, to move away from rearing sheep for their wool to keeping sheep for meat instead.
The study, spearheaded by China, is a collaboration between researchers working at universities in China, Iran, Pakistan, Indonesia, Nepal, Finland, and the U.K. The research is published in journal Molecular Biology and Evolution. The paper is titled “Mitogenomic meta-analysis identifies two phases of migration in the history of eastern Eurasian sheep.”
