奶牛CXCR1基因SNPs多态与白血病易感性的关联分析

发布时间：2018-05-19 11:32

  本文选题：荷斯坦牛 + 牛白血病　； 参考：《扬州大学》2016年硕士论文

【摘要】：牛白血病是由牛白血病病毒(BLV)引起的牛、绵羊等动物的慢性肿瘤性疾病,其特征是淋巴样细胞恶性增生和高死亡率。牛白血病分布十分广泛,存在于世界各个养牛国家,在某些牛群中血清阳性率甚至达到60%,是影响养牛业发展的重要传染病之一。目前国外对牛白血病的研究较多,通过前人不断研究已证明免疫系统在该病的发生及发病过程中起着重要作用。同时,CXCR1基因在奶牛炎症和肿瘤的发生、增殖、生长等方面发挥重要的调控作用。因此,本研究通过对某大型奶牛场886头中国荷斯坦牛血样进行采集,用BLV FRET-qPCR对牛白血病感染情况进行检测,同时收集采样牛只生产性能测定记录,采用多因素方差法分析白血病在不同产犊季节、测定季节、胎次和泌乳阶段对奶牛泌乳性能(日产奶量、乳脂率、乳蛋白率、体细胞评分、总固体、尿素氮)的影响。同时,用直接测序法对奶牛CXCR1基因编码区(CDS)突变进行检测,筛选出642GA、816CA、980GA和1068GA 4个SNP位点,再采用飞行时间质谱法对筛查出的突变位点进行SNP分型检测,采用Logistic回归分析CXCR1 SNPs基因型和单倍型与牛白血病的感染之间的关系,以期为牛白血病抗性的分子标记辅助育种提供参考依据,研究主要结果如下:1.在886头奶牛中,患有牛白血病的牛为48头,阳性检出率为5.4%。2.白血病对不同产犊季节、泌乳阶段、胎次及测定季节奶牛泌乳性能的影响都达到了极显著水平(P0.01)。春季测定阳性牛乳脂率、SCS显著低于阴性牛;泌乳中期阳性牛SCS显著低于阴性牛,泌乳末期阴性牛乳脂率显著高于阳性牛;三胎阴性牛尿素氮含量显著高于阳性牛;夏、冬季节产犊的阴性牛SCS显著高于阳性牛。3.CXCR1基因CDS区共发现13个SNP位点,经连锁分析分为4个连锁群。从4个连锁群中各选择1个SNP位点进行后续分析,分别是:642GA、816CA、980GA和1068GA4个SNP位点,利用飞行质谱法对大样本中国荷斯坦牛进行检测。CXCR1-642、CXCR1-816、CXCR1-980和CXCR1-1068 4个SNP位点优势基因型分别为GG、CC、GG和GG型,频率分别为0.58、0.466、0.60和0.658,优势基因分别为G、C、G和G,基因频率是0.76、0.69、0.78和0.81。4个SNP位点共有8种单倍型,其中单倍型GAAG频率最高(0.819),而单倍型GCAG频率最低(0.033)。CXCR1 980GA位点和单倍型GCAG对牛患白血病的相对风险影响显著(P=0.016)。980GA位点AA型基因的发生概率为GG型基因的5.04倍,CXCR1单倍型GCAG患牛白血病的风险是GAGG的1.97倍。
[Abstract]:Bovine leukemia is a chronic tumor disease caused by bovine leukemia virus (BLVV) in cattle, sheep and other animals. It is characterized by malignant proliferation of lymphoid cells and high mortality. Bovine leukemia is widely distributed and exists in various cattle countries in the world. In some cattle, the seropositive rate even reaches 60%, which is one of the important infectious diseases affecting the development of cattle industry. At present, there are many researches on bovine leukemia abroad. It has been proved that the immune system plays an important role in the occurrence and pathogenesis of bovine leukemia. At the same time, CXCR1 gene plays an important role in the regulation of inflammation and tumorigenesis, proliferation and growth of dairy cattle. Therefore, the blood samples of 886 Chinese Holstein cattle in a large dairy were collected, the infection of bovine leukemia was detected by BLV FRET-qPCR, and the records of production performance of sampled cattle were collected at the same time. Multivariate variance method was used to analyze the effects of different calving seasons, birth order and lactation stage on milk performance (daily milk yield, milk fat rate, milk protein rate, somatic cell score, total solid state, urea nitrogen) in dairy cows. At the same time, direct sequencing method was used to detect the mutation of CXCR1 gene coding region in dairy cattle, and four SNP loci were screened out. The four SNP loci were selected, and the mutation sites were detected by time-of-flight mass spectrometry (TF-MS). Logistic regression analysis was used to analyze the relationship between CXCR1 SNPs genotype and haplotypes and bovine leukemia infection in order to provide reference for molecular marker assisted breeding of bovine leukemia resistance. The main results were as follows: 1. Of the 886 cows, 48 had bovine leukemia, and the positive rate was 5. 442. 2. The effect of leukaemia on milk performance of dairy cows in different calving seasons, lactation stage, birth order and determination season reached a very significant level (P 0.01). In spring, the milk fat rate of positive cattle was significantly lower than that of negative cattle, the SCS of middle lactation positive cattle was significantly lower than that of negative cattle, the milk fat rate of late lactating negative cattle was significantly higher than that of positive cattle, the urea nitrogen content of three-foetus negative cattle was significantly higher than that of positive cattle, and in summer, The SCS of calving negative cattle in winter season was significantly higher than that of positive cattle. 3. A total of 13 SNP loci were found in the CDS region of CXCR1 gene, which were divided into 4 linkage groups by linkage analysis. One SNP locus was selected from each of the four linkage groups for follow-up analysis, namely: 642 GAY816CAN980GA and 1068GA4 SNP loci. The dominant genotypes of CXCR1-642 CXCR1-980 and CXCR1-1068 were GGCCCCG and GG type, respectively, in large sample Chinese Holstein cattle by using flight mass spectrometry (FMS) to detect CXCR1-816CXCR1-980 and CXCR1-980, respectively. The frequencies were 0.58 and 0.4660.60, respectively, and the dominant genes were G and G, respectively. The frequencies of the genes were 0.766, 0.699, 0.78 and 0.81.4, respectively, and there were 8 haplotypes. The frequency of haplotype GAAG is the highest (0.819), while the frequency of haplotype GCAG is the lowest (0.033%). CXCR1 980GA site and haplotype GCAG have significant influence on the relative risk of bovine leukemia. The risk of bovine leukemia is 1.97 times higher than that of GAGG.
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S858.23
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本文编号：1909935