中国荷斯坦牛IRAK2基因遗传多样性与乳腺炎的相关性研究

 【目的】研究中国荷斯坦牛白细胞介素1受体相关激酶2(IRAK2)基因上5个SNP位点的多态性与奶牛体细胞评分（SCS）的相关性，为奶牛抗乳腺炎育种提供理论基础。【方法】采用PCR-RFLP技术、CRS-PCR技术和DNA测序，对1 292头中国荷斯坦牛、129头鲁西黄牛、32头渤海黑牛IRAK2基因g.28879、g.28916、g.29212、g.40035和g.40120共5个SNP位点进行研究，通过SAS软件进行相关性分析并采用SHEsis软件进行单倍型分析。【结果】共构建出30种单倍型，发现71种单倍型组合；对个体数量大于8头的单倍型组合与SCS进行关联分析表明，H21H23(TTAGGCTCCC)单倍型组合SCS最低。各个位点基因型与SCS关联分析表明，28 879突变位点的CC基因型个体SCS显著低于CT基因型个体(P＜0.05)，28 916突变位点的GG基因型个体SCS显著低于AG基因型个体(P＜0.05)，而其它3个位点不同基因型之间与SCS没有显著差异(P＞0.05)。【结论】H21H23单倍型组合在SCS方面为有利单倍型组合，可作为选择抗乳腺炎奶牛个体的分子遗传标记。

Study on Polymorphisms of IRAK2 Gene and Its Association with Mastitis in Chinese Holstein Cattle

【Objective】 The associations among five single nucleotide polymorphisms (SNPs) in interleukin-1 receptor associated kinase 2 (IRAK-2) gene and somatic cell score (SCS) in Chinese Holstein Cattle were investigated. 【Method】 A herd of 1 292 dairy cows, 129 Luxi Yellow Cattle and 32 Bohai Black Cattle from Shandong province and Tianjin were used as experimental materials. Polymerase chain reaction (PCR) - restriction fragment length polymorphism (RFLP), created restriction site (CRS)-PCR and sequencing methods were applied to analyze the polymorphisms of five loci (g.28879, g.28916, g.29212, g.40035, and g.400120) in IRAK-2 gene. The associations between SNPs and SCS were analyzed by the least-squares method as applied in the GLM procedure of SAS 8.1 and haplotype analysis was performed by SHEsis software.【Result】The results of haplotype analysis of five SNPs showed that 30 different haplotypes and 71 haplotype combinations were identified. The value of SCS of individuals with H21H23 (TTAGGCTCCC) was the lowest through the result of association between polymorphisms of IRAK-2 gene and SCS. Statistical analyses revealed significant associations between genotype CC and CT in position 28 879, and between GG and AG in position 28 916. The SCS value of genotype CC and GG was lower than that of CT and AG, respectively (P＜0.05), whereas no significant differences were detected among the positions 29212, 40035, 40120 and SCS (P＞0.05).【Conclusion】The haplotype combination H21H23 was a favorable haplotype combination to the SCS. It may be used as a possible candidate for the molecular markers of mastitis resistance in dairy cattle breeding program.