荷斯坦奶牛泌乳曲线及与产奶性状相关的AGPAT6、ABCA1基因的多态性研究

发布时间：2018-05-18 12:10

本文选题：荷斯坦奶牛 + 泌乳曲线　；参考：《广西大学》2015年硕士论文

【摘要】：本研究采用Wood等四种模型分别对荷斯坦奶牛泌乳曲线进行拟合,以期选出最佳拟合模型,为准确预测该牛场奶牛305d产奶量奠定基础,并为进一步研究荷斯坦奶牛的生产性能和泌乳规律提供参考依据；采用DNA池和PCR-SSCP法筛选AGPAT6和ABCA1基因SNP位点,结合HRM技术进行基因分型,研究基因变异和产奶量及奶成分的相关性；并进一步对AGPAT6基因mRNA的表达分析和启动子甲基化分析,初步为揭示AGPAT6基因影响奶牛产奶性状的分子调控机制提供理论基础。研究结果如下：1.荷斯坦奶牛泌乳曲线的拟合分析利用SPSS17.0软件对荷斯坦奶牛305d产奶量进行曲线拟合。结果表明：六次多项式模型为荷斯坦奶牛最佳泌乳曲线模型,其对各胎次泌乳曲线的拟合效果都较为理想。模型极显著影响泌乳曲线的拟合度R2(P0.01),胎次对泌乳曲线拟合度R2无显著性影响(P0.05)。2.AGPAT6基因多态性及其与产奶性状的相关分析(1)AGPAT6基因8个(P1～P8)基因座中,在P1(exon1)、P2(exon3)、 P3 (intron3)、P6 (intron8)、P7 (intron9)和P8 (intron11)中各检测到1个SNP,P4和P5中没有检测到多态性位点。每个SNP均有三种基因型。实验牛群在这6个SNP s均处于中度多态(0.25PIC0.5)。(2)利用SPSS17.0软件中的最小二乘法线性拟合模型对6个SNP s与奶牛产奶量和乳成分进行相关性分析。结果表明：P1位点不同基因型显著影响乳成分(P0.05),P2、P3、P6和P8位点的不同基因型显著影响产奶量和乳成分,P7位点不同基因型显著影响产奶量、乳脂率和非脂固形物(P0.05),乳蛋白率无显著差异(P0.05)。3.ABCA1基因多态性及其与产奶性状的相关分析在ABCA1基因3个外显子中,只在exon7中检测到一个SNP。此位点有TT、TC和CC三种基因型。实验牛群在此位点为中度多态(0.25PIC0.5),处于Hardy-Weinberg不平衡状态。将此位点与荷斯坦奶牛的产奶性状进行相关分析,发现不同基因型个体的产奶量存在极显著差异(P0.01),而不同基因型个体乳脂率和乳蛋白率无显著性差异(P0.05)。4.AGPAT6基因mRNA表达分析和启动子甲基化分析(1)利用奶牛乳汁体细胞提取总RNA,研究同胎次产奶量接近而乳脂率不同的AGPAT6基因P2位点不同基因型个体mRNA表达水平。结果表明：TT型和TC型个体mRNA表达水平显著高于CC型(P0.05),其mRNA表达水平与奶牛乳脂率正相关。(2)利用MS-PCR法分析AGPAT6基因P2位点不同基因型个体启动子甲基化水平。结果表明：TT、TC和CC基因型个体启动子甲基化状态与基因表达未呈现一致的规律趋势,表明P2位点不同基因型个体]mRNA表达水平可能不受AGPAT6基因启动子甲基化过程的调控。
[Abstract]:In this study, Wood and other four models were used to fit the lactation curve of Holstein cows respectively, in order to select the best fitting model, and to lay the foundation for accurately predicting the milk yield of the dairy cows in 305 days. It also provides reference for further study on production performance and lactation law of Holstein cows, screening AGPAT6 and ABCA1 gene SNP loci by DNA pool and PCR-SSCP method, and carrying out genotyping with HRM technique. To study the correlation between gene variation and milk yield and milk composition, and to further analyze the expression of AGPAT6 gene mRNA and promoter methylation analysis, to provide a theoretical basis for revealing the molecular regulation mechanism of AGPAT6 gene affecting dairy cow milk production traits. The results are as follows: 1. Fitting Analysis of lactating Curve of Holstein Dairy cows the milk yield of Holstein cows at 305 days was fitted by SPSS17.0 software. The results showed that the six degree polynomial model was the best lactation curve model for Holstein cows, and the fitting effect of the curve was satisfactory. The model had a significant effect on the fitting degree of lactation curve R _ 2 / P _ (0.01), but the number of births had no significant effect on the fitness of milk curve R ~ (2). The polymorphism of AGPAT6 gene and its correlation with milk yield traits were analyzed in the locus of 8 (P1 / P8) gene of AGPAT6 gene, and the relationship between the polymorphism of AGPAT6 gene and lactation traits was analyzed. No polymorphic loci were detected in P1 exon1, P6 intron8, P7 intron9 and P8 intron11, respectively, in P1exon3, P3 intron3 and P6 intron8 intron9 and P8 intron11, respectively. No polymorphic loci were detected in P4 and P5. Each SNP has three genotypes. The correlation between six SNP s and milk yield and milk composition was analyzed by using the least square linear fitting model in SPSS17.0 software. The results showed that the different genotypes of different genotypes at the P1 locus significantly affected the milk yield and the milk yield of P0.05, P2, P3, P6 and P8 loci, and the milk yield was significantly affected by different genotypes of P7 locus. There was no significant difference between milk fat rate and non-fat solids (P0.05), and there was no significant difference in milk protein rate. The polymorphism of ABCA1 gene and its correlation with milk yield traits were detected only in exon7 and 3 exons of ABCA1 gene. There were three genotypes of TTTC and CC at this locus. The experimental cattle were in the Hardy-Weinberg imbalance state at this site, which was a moderate polymorphic 0.25PIC0.5. The correlation between this locus and milk yield traits of Holstein cows was analyzed. It was found that there were significant differences in milk yield among individuals with different genotypes (P 0.01), but there was no significant difference in milk fat and milk protein rates among individuals with different genotypes. AGPAT6 gene mRNA expression analysis and promoter methylation analysis were used to analyze milk somatic cells of dairy cows. Total RNAs were extracted to study the expression level of mRNA in individuals with different genotypes of AGPAT6 gene P2 locus with similar milk yield and different milk fat percentage. The results showed that the level of mRNA expression in individuals with different genotype P2 of AGPAT6 gene was significantly higher than that of P0.05 of CC type, and the mRNA expression level was positively correlated with milk fat rate of dairy cows.) the promoter methylation level of different genotype individuals with P2 locus of AGPAT6 gene was analyzed by MS-PCR method. The results showed that the methylation status of promoter in individuals with different genotypes of AGPAT6 and CC was not consistent with the trend of gene expression, indicating that the level of mRNA expression in individuals with different genotypes at P2 locus might not be regulated by the methylation process of promoter of AGPAT6 gene.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S823

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