Abstract: In this study, liver DNA from purebred Ningxia Tan sheep, purebred Xinjiang fine-wool sheep and purebred Tibetan sheep was extracted followed by genomic library construction, amplification, purification and quality control. Simple sequence repeat (SSR) sites in the sequence were detected, and 50 pairs of primers were designed, synthesized and screened for polymerase chain reaction (PCR) amplification. SSR typing was carried out by capillary electrophoresis, and polymorphic primers were selected to detect the genetic polymorphism of the three breeds. The results showed that 10 pairs of SSR primers successfully amplified stable bands. Ten pairs of polymorphic SSR primers were used to analyze the genetic diversity of Ningxia Tan sheep, Xinjiang fine-wool sheep and Tibetan sheep, showing an average number of alleles (Na) of 4.100, 3.100 and 3.600, average number of effective alleles (Ne) of 3.782, 2.747 and 3.193, average observed heterozygosity (Ho) of 1.007, 1.009 and 0.953, average expected heterozygosity (He) of 0.704, 0.615 and 0.660, and average polymorphic information content (PIC) of 0.432, 0.414 and 0.425, respectively. These data indicated that the genetic polymorphism of Ningxia Tan sheep was higher than that of Tibetan sheep and Xinjiang fine-wool sheep. The results of capillary electrophoresis with fluorescence detection showed that the fluorescent primers scaffold632:150-463, scaffold31384:146-461 and scaffold7676:103-270 had excellent specificity for Ningxia Tan, Xinjiang fine-wool and Tibetan sheep, respectively, and they could effectively distinguish the breeds. In conclusion, the gene banks established can allow scientific and accurate identification of Ningxia Tan sheep, Tibetan sheep and Xinjiang Fine-wool sheep.

Key words: genomic DNA; microsatellite sequence; specific detection; breed identification of ovine livers