Abstract: Tan sheep, not only famous for its delicious meat, but also enjoys high reputation at home and abroad for its one-month lamb's fur. Therefore, the coat color is an important economic trait of Tan sheep. To detect the genomic regions which affecting the coat color of Tan sheep, the genome-wide association studies (GWAS) were performed based on Logistic regression method using genotypes from the America Affymetrix 600K genotyping chips for this trait. Genotyping was performed on 96 representative tan sheep of Yanchi, Ningxia, which had pure white bodies, white bodies with black heads and white bodies with brown or yellow heads. By Bonferroni correction, we have found five SNPs significantly associated with coat color, which were located within or close to 2 known genes (MC1R and TCF25). The MC1R is involved in the regulation of melanin synthesis that has been shown to be related to the color of sheep by numerous studies. The TCF25 is located nearby MC1R, so the identification of TCF25 maybe a result of linkage disequilibrium between these two genes. Our studies explained the genetic mechanism of coat color of Tan sheep, and provided scientific basis for assisted breeding by mark the color traits of Tan sheep.

Key words: Tan sheep, coat color, genome-wide association study