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【目的】探索ERAP2,Cwc27,PPFIBP2,THADA,ZNF804B和AMHR2基因多态性与新疆褐牛体细胞评分及泌乳性状的相关性,旨在寻找与新疆褐牛体细胞评分及泌乳性状相关的分子标记。【方法】以新疆乌鲁木齐种牛场、新疆天山畜牧生物工程股份有限公司共169头新疆褐牛母牛为试验对象,以2008—2015年间的生产性能测定记录(包括乳脂率、乳蛋白率、总固体含量、乳糖率和体细胞计数等)和305 d产奶量为试验数据,基于课题组前期15头中国荷斯坦牛DNA混池重测序的结果筛选外显子区域10个SNPs,采用基质辅助激光电离飞行时间质谱法(sequenom mass Array genotype)分型技术验证10个SNP位点的遗传多态性,运用SAS8.1软件GLM过程对这10个SNP突变与新疆褐牛体细胞评分(SCS)、305 d产奶量、乳脂率、乳蛋白率、乳糖率和总固体的关联程度进行统计分析。【结果】10个SNP位点均具有多态性,χ~2检验表明群体中9个SNP位点符合Hardy-Weinberg平衡状态。关联分析结果表明ERAP2基因两个位点(T98741711C和G98736141A)均与新疆褐牛305 d产奶量达到极显著关联(P<0.001),其中TT型和GG型个体的产奶量最高;PPFIBP2(C45667492G)位点与新疆褐牛乳糖率达到显著关联(P<0.005),其中GG型个体的乳糖率最高;Cwc27(T14533269A)位点与新疆褐牛乳脂率和总固体含量达到显著关联(P<0.005),与SCS达到极显著关联(P<0.001),其中TT型个体的乳脂率和总固体含量均最高,AA型个体的SCS极显著高于AT和TT型;AMHR2(C26758055G)位点与新疆褐牛乳蛋白率和总固体含量达到极显著关联(P<0.001),其中GG型个体显著高于CC和GC型个体。连锁不平衡分析与单倍型构建的结果发现10个SNPs构建了两个单倍型模块,其中SNP1和SNP2位点之间处于连锁不平衡状态(r2>0.3),SNP4和SNP10位点之间处于强连锁不平衡状态(r2>0.6),随后分析了单倍型与SCS和泌乳性状之间的相关性,发现单倍型与新疆褐牛SCS和泌乳性状无显著关联(P>0.001)。【结论】初步发现了ERAP2,Cwc27,PPFIBP2和AMHR2与新疆褐牛SCS和泌乳性能相关,结果可为新疆褐牛产奶性状的分子标记辅助选育提供参考和依据。
【Objective】 To explore the relationship between ERAP2, Cwc27, PPFIBP2, THADA, ZNF804B and AMHR2 gene polymorphisms and somatic cell score and lactation traits in Xinjiang brown cattle, and to find molecular markers related to somatic cell score and lactation traits in Xinjiang brown cattle . 【Method】 A total of 169 Xinjiang brown cow cows from Urumqi cattle farm in Xinjiang and Xinjiang Tianshan Livestock Breeding and Biological Engineering Co., Ltd. were used as experimental subjects. The performance records of milk production, including milk fat percentage, milk protein percentage, Solid content, lactose rate and somatic cell count) and 305 days of milk production were used as experimental data to screen 10 SNPs in the exon region based on the results of 15 new Chinese Holstein cattle DNA pool reanalysis in the previous period. The genotypes of 10 SNPs were tested by laser ionization time-of-flight mass spectrometry (sequenom mass array genotyping). The genetic polymorphisms of these 10 SNPs were compared with Xinjiang brown cattle somatic cell score (SCS) using SAS8.1 software GLM process. , 305 d milk yield, milk fat percentage, milk protein percentage, lactose rate and total solid correlation analysis. 【Result】 All 10 SNPs were polymorphic. The results ofχ ~ 2 test showed that 9 SNPs in the population were in accordance with Hardy-Weinberg equilibrium. Correlation analysis showed that ERAP2 gene two loci (T98741711C and G98736141A) were significantly correlated with 305-day milk production of Xinjiang brown cattle (P <0.001), among which, TT and GG individuals had the highest milk yield; PPFIBP2 C45667492G) was significantly correlated with the lactose content of Xinjiang brown cattle (P <0.005), of which GG type had the highest lactose rate. The Cwc27 (T14533269A) locus was significantly associated with the milk fat percentage and total solid content of Xinjiang brown cattle (P < (P <0.001). The TT rate and the total solid content of TT individuals were the highest, while those of AA individuals were significantly higher than those of AT and TT genotypes. The frequencies of AMHR2 (C26758055G) Xinjiang brown milk protein ratio and total solids content reached a significant correlation (P <0.001), of which GG type was significantly higher than CC and GC type individuals. The results of linkage disequilibrium analysis and haplotype construction showed that 10 SNPs constructed two haplotype modules, in which the SNP1 and SNP2 loci are in linkage disequilibrium (r2> 0.3), SNP4 and SNP10 loci (R2> 0.6). Subsequently, the correlation between haplotypes and SCS and lactation traits was analyzed. It was found that there was no significant association between haplotypes and SCS and lactation traits in Xinjiang brown cattle (P> 0.001). 【Conclusion】 The results showed that ERAP2, Cwc27, PPFIBP2 and AMHR2 were correlated with SCS and lactation performance of Xinjiang brown cattle. The results may provide reference and basis for molecular marker assisted selection of milk traits in Xinjiang brown cattle.