Genetic differentiation and phylogeny of 27 sheep populations based on structural gene loci.

To explore the genetic divergence and phylogeny of Chinese indigenous sheep breeds, in the current study, we analyzed the polymorphisms of 5 structural loci in ten sheep populations, including Sishui Fur, Sunite, Wurank, Bayinbuluke, Altay, Small-Tailed Han, Wadi, Tan, Tong and Hu sheep. The data were then compared with those from an additional 13 Asian and 4 European sheep populations acquired by the same experimental method. Based on the genetic distance and the results of a cluster analysis, we constructed the phylogenetic relationship of 27 populations. The results showed that the sheep populations in this study could be classified into four genetic groups: "Mongolian", "Tibetan", "South-Southeast Asian" and "European" sheep groups. All 10 Chinese sheep breeds belonged to the "Mongolian sheep" lineage; however, Finnish Landrace sheep and Yunnan sheep could not be classified into any of the four groups. These results could provide a good reference for the protection and utilization of primary breed resources in China and phylogenic research on Asian sheep populations.