[Single nucleotide polymorphism in exon partial sequence of sow kappa opioid receptor gene].

The possibility of the Kappa opioid receptor (KOR) gene as the candidate gene affecting the stereotyped behavior traits in sows was discussed in the current study. Based on the exon partial sequence of sow KOR gene, three pairs of primers were designed to analyze single nucleotide polymorphisms to develop PCR-SSCP method in Landrace, Yorkshire and Duroc breeds. One polymorphism, found in PCR product amplified with F1/R1, was caused by a single nucleotide mutation of C to T at the position of mRNA 105 compared with the sequence published in GenBank, which was a silence mutation. The results of chi2 test showed that the frequencies of genotypes in different breeds were different significantly (P<0.01). The least square analysis between three genotypes and the stereotyped behavioral traits showed that individuals with BB genotype had significantly higher (P<0.01) still standing behaviors than those with AA and AB genotype, but no difference were found in other behavioral traits. According to the above results, we may conclude that SNP of KOR gene has effect on the still standing behavioral trait of sows.