摘要
采用PCR-SSCP技术并结合测序对233头奶牛β乳球蛋白(β-Lg)基因5’端部分序列和外显子1全部序列进行了多态性研究,分析了该基因与奶牛泌乳性状的相关性。结果表明:β-Lg基因5’端和外显子1共存在2个等位基因3种基因型,BB型为优势基因型,B为优势等位基因。该群体在这一位点上偏离Hardy-Weinberg平衡状态,多态信息含量(PIC)为0.3548。测序结果显示,与普通牛该基因序列(X14710)相比,B等位基因在2073 bp、2202 bp和2206 bp处发生了G→C、C→T和A→G的碱基突变,其中2202 bp处的C→T突变导致第11位氨基酸由苏氨酸变为异亮氨酸,而A等位基因在3个位点上与X14710相同。最小二乘法分析表明,BB型305 d乳蛋白量显著高于AA型和AB型(P<0.05);AB型305 d乳脂量显著高于AA型(P<0.05),BB型与AB型之间差异不显著(P>0.05);等位基因B为高乳蛋白量和乳脂量的优势基因,可作为奶牛选育的分子遗传标记。
PCR-SSCP polymorphism of β-Lactoglobulin（β-Lg） gene partial sequence of 5＇UTR and whole exon 1 and correlation with milk performances were studied in 233 dairy cattles.The results showed that there were two alleles and three genotypes in the locus of β-Lg gene 5＇UTR and exon 1,and type BB was dominant genotype and B allele was dominant allele.The population was deviated from Hardy-Weinberg equilibrium at this locus,and the polymorphism information content（PIC） was 0.3548.The sequencing result showed that,comparing with the sequence（X14710） of normal cattle,there were site mutations G→C,C→T and A→G existed in allele B at the 2073 bp,2202 bp and 2206 bp,respectively,and the second site mutation at 2202 bp causing Threonine transformed into Isoleucine.However,the same sequences of these 3 sites were observed between allele A and X14710.The result of Least Squares analysis showed that： 305 d milk protein of BB type was significantly higher than types AA and AB（P〈0.05）;305 d milk fat yield of type AB was significantly higher than type AA（P〈0.05）,and no significant difference was observed between BB and AB genotypes（P〈0.05）.In conclusion,allele B was the dominant allele of high milk protein and milk fat yield,which can be considered as the molecular genetic marker of dairy cattle breeding.
出处
《四川动物》
CSCD
北大核心
2013年第5期701-706,共6页
Sichuan Journal of Zoology
基金
科技部星火计划项目(2008GA860014)
甘肃省生物技术专项(GNSW-2009-08)
