荷斯坦牛血浆催乳素浓度遗传参数估计及其与PRL、PRLR和TRH基因关联分析

为探究奶牛血浆催乳素(Prolactin, PRL)浓度的群体特征及其在不同环境条件和生理阶段下的变化规律，估计牛血浆PRL浓度的遗传参数，探究PRL、PRLR和TRH基因多态性与血浆PRL浓度之间的相关性，本研究于2014和2017年对北京地区某规模化牧场的472头泌乳期荷斯坦牛进行血浆PRL浓度测定，共获得1 169条数据。首先，采用固定模型分析采样季节、胎次、挤奶前后和泌乳阶段对奶牛血浆PRL浓度的影响；然后，采用重复力动物模型估计血浆PRL浓度的遗传参数；此外，通过扫描PRL、PRLR和TRH基因的多态位点，对血浆PRL浓度进行基于多态位点和单倍型的关联分析。结果显示：1)泌乳期荷斯坦牛血浆PRL平均浓度为224.29 mIU/L,胎次、采样季节和泌乳阶段对血浆PRL浓度有显著或极显著影响，血浆PRL浓度随胎次和泌乳阶段的推移而逐渐升高，春季和夏季时奶牛血浆PRL浓度极显著高于秋季和冬季(P<0.01);2)血浆PRL浓度的遗传力为0.02,为低遗传力性状；3)PRL和PRLR基因基因中未发现与血浆PRL浓度显著相关的SNP位点，TRH基因的rs137596325、rs1...

Genetic parameters of plasma prolactin concentration and its association with gene PRL, PRLR and TRH in Holstein cattle

In order to explore the population characteristics of plasma prolactin(PRL)concentration in dairy cows and its variation under different environmental conditions and physiological stages, estimate the genetic parameters, and estimate the association between polymorphism of gene PRL, PRLR, TRH and plasma PRL concentration, a total of 1 169 records of plasma PRL concentration from 472 lactating Holstein cows were tested in a large-scale dairy farm in Beijing in 2014 and 2017. Firstly, the effects of sampling season, parity, milking status and lactation stage on plasma PRL concentration were analyzed by employing a fixed model. Then, the genetic parameters of plasma PRL concentration were estimated using a repeatability animal model. In addition, polymorphic loci of gene PRL, PRLR and TRH were screened in Holstein cattle; and the SNP- and haplotype-based association analyses were performed with plasma PRL concentration. The results showed that: 1)The average plasma PRL concentration of Holstein cattle was 224. 29 mIU/L. Parity, sampling season and lactation stage had significant or highly significant impacts on plasma PRL concentration. Plasma PRL concentration gradually increased with the increase of parity and lactation stage, and plasma PRL concentration in spring and summer were extremely significantly higher than that in autumn and winter(P<0. 01); 2)The heritability of plasma PRL concentration was 0. 02, indicating a lowly inheritable nature; 3)Association analyses showed that no SNP within gene PRL and PRLR had significant effect on plasma PRL concentration; rs137596325, rs109144892, rs108991567, rs109468305 and rs109330999 within gene TRH had significant or highly significant effects on plasma PRL concentration. Based on linkage disequilibrium analysis of SNPs in three genes, haplotype block in PRLR gene tended to associate with plasma PRL concentration(P<0. 1), and two haplotype blocks in TRH gene were significantly associated with plasma PRL concentration. In conclusion, this study obtained the population characteristics, genetic parameters and associated genetic markers for plasma PRL concentration in Holstein cows, which was beneficial for further understanding the genetic mechanism of plasma PRL concentration.