GnRH和LHR基因多态性和牛精液品质性状的相关分析

本试验采用PCR—RFLP方法分析了GnRH基因外显子2和LHR基因内含子9在144头中国荷斯坦牛和79头河南地方肉牛品种中的多态性，利用最小二乘法分析多态位点不同基因型与精液品质性状的关系。研究结果表明，2～3岁荷斯坦牛的鲜精活力显著高于4岁以上的牛，而畸形率显著低于7岁以上的牛。对2～4岁荷斯坦牛不同精液品质性状的简单相关分析表明，畸形率与顶体完整率和冻精活力呈显著的负相关（相关系数r分别为-0．736和-0．500）。不同基因型与精液品质性状的关联分析结果表明，144头中国荷斯坦牛所研究位点不同基因型对精液品质性状没有显著影响。而河南地方肉牛GnRH基因外显子2的A883G位点GG基因型的精子密度显著低于AA和AG基因型．LHR基因G51656T位点的TT基因型精子密度显著高于GT基因型，未检测到GG基因型。并且发现随着年龄的增长，种公牛的精液品质逐渐变差。GnRH和LHR基因可作为影u向肉牛精液品质性状的候选基因。

Polymorphisms in GnRH and LHR Genes and Their Effects on Bulls Sperm Quality Traits

Polymorphisms of GnRH exon 2 and LHR intron 9 was detected by PCR-RFLP method in 144 Chinese Holstein bulls and beef bulls. Effects of genotypes on sperm quality traits were conducted by least-squares means method. Bulls for the age of 2~3 years had higher fresh sperm quality than bulls above 4 years, however, they had lower abnormal sperm rate than bulls above 7 years. Phenotypic correlation analysis showed that significant negative correlations were observed between ASR and AIR（r=-0.736, P〈0.01）, ASR and AIR （r=-0.500, P〈O.01） respectively. There were moderate positive correlations between VOL and SD （r=0.422, P〈O.O1）, as well as FSM（I=0.411, P〈0.01）. The different genotypes had no significant effects on Chinese Holstein bull sperm quality traits. In beef bulls, bulls with GG genotype in GnRH exon 2 （A883G） had significant lower sperm density than bulls with AA and AG genotype, TF genotype of LHR at G51656T had higher sperm density than bulls with GT genotype. In conclusion, with the increasing of age, bulls sperm quality become worse; GnRH and LHR may be candidate genes for sperm quality of beef bull.