秦川牛Chemerin基因第2和第6外显子的SNPs检测及其与肉质性状的相关性

Polymorphism of Chemerin gene and its relationship with meat quality traits in Qinchuan cattle

【目的】对秦川牛Chemerin基因第2和第6外显子进行SNPs检测,并研究其与秦川牛肉质性状的相关性。【方法】采用DNA直接测序技术并结合PCR-SSCP方法,对324头2~3岁秦川牛Chemerin基因第2和第6外显子进行多态性分析,用最小二乘法拟合线性模型对Chemerin基因不同基因型与秦川牛肉质性状（宰前活质量、胴体质量、背膘厚、大理石花纹评分、系水力、眼肌面积和嫩度）进行关联分析。【结果】秦川牛Chemerin基因第2外显子868 bp处发生了A→G突变,第6外显子2 948 bp处发生了C→G突变;用PCR-SSCP方法检测得到AA、AG、GG、EE和EF 5种基因型,其基因型频率分别为0.219 1,0.432 1,0.348 8,0.348 4和0.651 6,均处于中度多态,其中C2948G位点处于Hardy-Weinberg极度不平衡状态（P〈0.01）。关联分析结果表明,秦川牛Chemerin基因第2外显子AA基因型与眼肌面积、背膘厚、大理石花纹评分和系水力均显著相关（P〈0.05）;第6外显子各基因型与供试肉质性状间没有相关性（P〉0.05）。【结论】Chemerin基因第2外显子可能是影响秦川牛眼肌面积、系水力和大理石花纹评分等肉质性状的主效QTL或与之紧密连锁,可以尝试将其用作秦川牛品质改良的辅助选择标记。

【Objective】 The variation of Exon 2 and Exon 6 of Chemerin gene were examined and the association of this polymorphism with meat quality traits in Qinchuan cattle was investigated.【Method】 Using PCR-SSCP and DNA sequencing technology,324 individual Qinchuan heifers aged 2 to 3 years were selected to check the polymorphism of Exon 2 and Exon 6 of Chemerin gene.Least squares regressions analysis with linear mode was used to analyze the relationship between the genotypes and meat quality traits.【Result】 Mutations of A868G and C2948G were detected in the Exon 2 and Exon 6,respectively.Five genotypes（AA,AG,GG,EE and EF） were found by PCR-SSCP.And the genotypic frequencies of them were 0.219 1,0.432 1,0.348 8,0.348 4 and 0.651 6,respectively.Both of them were in moderate diversity,while the C2948G location was not in Hardy-Weinberg balance（P0.01）.Association analysis of polymorphisms with meat quality traits showed that：the genotype AA was significantly related to the loin muscle area,marbling score and the water holding capability of Exon 2 of Chemerin gene（P0.05）,while there was no significant association in the live weight,carcass weight and meat tenderness（P0.05）.The results also showed that Exon 6 polymorphism had no association with any meat quality traits.It may mean that there is no correlation between the polymorphism and the meat quality traits.【Conclusion】 We conclude that Chemerin gene Exon 2 may be closely related to the meat quality traits,such as loin muscle area,water holding capability and marbling score,and it could be a candidate molecular marker for the quality improved of Qinchuan cattle.