Abstract：Thyroid-stimulating hormone receptor (TSHR) may play important roles in process of seasonal breeding in mammals mediated by photoperiod, but the hereditary character and molecular mechanism in sheep (Ovis aries) are still unclear. Therefore, the T481C locus on exon 10 of TSHR in our unpublished chip date was chosen as candidate SNP, polymerase chain reaction-single strand conformation polymerase (PCR-SSCP) method was used to detect genotypes in six sheep breeds which have differences in reproductive characteristics (Altay, Chinese Merino, Suffolk, Duo Lang, Hu and Small Tail Han Sheep). The results showed that the T-C point mutation was detected in 481 bp of exon 10 of TSHR gene in sheep, which was a silent mutation, three genotypes (TT, TC and CC) were found, TT genotype at T481C locus was preponderant genotype in non-seasonal breeding sheep flocks (Small tail han sheep and Duo lang sheep), while the lowest percentage of the genotype in seasonal breeding sheep flocks(Altay, Chinese merino and Suffolk) is only 8%. Analysis of variance suggested T481C was significantly different between the allele frequencies in seasonal and non-seasonal breeding sheep breeds(P＜0.01). These results suggest that there is a big difference in the SNP distribution between seasonal breeding and non seasonal breeding sheep populations, and the SNP can be used as an ideal molecular marker in non-seasonal reproduction sheep breeding.
