MBL1基因第一内含子与第二外显子多态性与中国荷斯坦牛乳腺炎和乳品质的关联分析

【目的】研究中国荷斯坦牛MBL1基因第一内含子与第二外显子多态性及分析MBL1基因遗传多态性与乳腺炎和乳品质的关联性,为培育优质抗性奶牛提供参考依据。【方法】采用PCR、DNA测序和PCR-RFLP技术,对596头中国荷斯坦牛的MBL1基因内含子1和外显子2序列进行了研究,通过SHEsis软件进行配对连锁不平衡分析和单倍型分析。【结果】发现3个新的SNPs,包括内含子1上G855A1个SNP位点;外显子2上G2651A突变为错义突变,导致第24位氨基酸由缬氨酸变为异亮氨酸;T2686C突变为同义突变,仍编码丙氨酸。单位点基因型与泌乳性状关联分析表明,G2651A突变位点AA基因型个体体细胞评分(SCS)显著高于GG、GA基因型个体(P0.05);G855A、T2686C位点的突变与体细胞评分、乳脂率、乳蛋白率、305d产奶量相关性都不显著。共构建出8种单倍型,发现19种单倍型组合;其中H2H2单倍型组合个体乳蛋白率、体细胞评分为最高;H3H7单倍型组合个体体细胞评分最低,与H2H2个体差异极显著;H4H4单倍型组合个体305d产奶量最高。【结论】H3H7可作为乳腺炎抗性选择的分子标记。H2H2单倍型组合个体虽然乳蛋白率最高,但体细胞评分也最高,对乳腺炎易感,为不利单倍型组合。H4H4单倍型组合305d产奶量最高,对乳蛋白率、乳脂率和体细胞评分影响不大,所以此种基因型组合可以用来提高产奶量。

Polymorphisms of MBL1 Gene Intron 1 and Exon 2 and Its Association with Mastitis and Milk Quality in Chinese Holstein Cattle

【Objective】 The polymorphisms of MBL1 gene intron1 and exon2 and their correlation to mastitis and milk quality in Chinese Holstein cattle were investigated for the purpose of providing molecular maker information to facilitate the breeding efficiency of high-quality resistant cow. 【Method】 Sequencing, PCR-RFLP and CRS-PCR were applied to analyze the polymorphisms of three loci in MBL1 gene intron1 and exon2 in 596 Chinese Holstein cattle. Linkage disequilibrium and haplotype were analyzed using SHEsis Software. 【Result】 One SNP in the intron1 G855A and two SNPs in the exon2 G2651A (Val24Ile), T2686C (Ala35Ala) were found.At locus G2651A, the cows with genotype AA showed higher somatic cell score than those with genotypes GG and GA (P＜0.05), but there were no correlation between the SNP G855A, T2686C and somatic cell score, fat rate, protein rate and 305 d milk yield. Eight haplotype and 19 haplotype combinations were found in 596 Chinese Holstein cattle. The cows with haplotype combination H2H2 had the highest protein rate and somatic cell score. Haplotype combination H3H7 had the lowest somatic cell score. The cows with haplotype combinations H4H4 had the highest 305 d milk yield. 【Conclusion】 Considering the distribution frequencies of haplotype combinations, MBL1 gene H3H7 is a favorable haplotype combinations to the mastitis resistance selection and H4H4 can be chosen as the molecular markers for choosing high milk yield.