水牛κ-酪蛋白基因(CSN3)外显子4序列多态性研究

Polymorphisms of the Exon 4 in CSN3 Gene of Buffalo(Bubalus bubalis)

分别设计位于CSN3 5个外显子旁侧引物,采用DNA测序法对沼泽型和河流型水牛CSN3编码区结构进行了分析,并对10个水牛群体共106个样本CSN3第4外显子序列进行了变异检测。结果表明,两类水牛CSN3编码区由848个核苷酸组成,包括ORF序列573bp、5′-UTR序列69bp和3′-UTR序列206bp。在水牛CSN3第4外显子中共检测到4个SNP,其中c.445G>A,c.467C>T和c.516A>C为异义替换,导致相应的κ-CN成熟肽中氨基酸发生p.Val128Ile、p.Thr135Ile和p.Glu151Asp改变,c.467C>T和c.516A>C替换可能对κ-CN功能产生了影响。群体遗传分析表明,在河流型水牛中,等位基因c.445G、c.467C、c.471C和c.516A均为优势等位基因,而在沼泽型水牛中,仅c.445G、c.467C和c.471C为优势等位基因,河流型和沼泽型水牛的遗传差异主要体现在SNP516位点的群体遗传组成上。

κ-CN not only plays a crucial role in the formation of stable casein micelles,but also has a major influence on clotting properties and milk yield according to the studies in Bos taurus.But there are few studies on the variation within CSN3 and its association with production traits in buffalo.All 5 exons of CSN3 in buffalo were separately amplified via 5 PCRs and sequenced,then,the polymorphisms of exon 4 in CSN3 for 106 individuals sampled from 10 river and swamp buffalo populations were assayed by using DNA sequencing.Complete CDS sequence of CSN3 in buffalo was composed of 848 nucleotides,which included 5′ UTR comprising 69 nucleotides,an open reading frame of 573 nucleotides and 3′ UTR consisting of 206 nucleotides.A total of 4 polymorphisms were discovered in the exon 4 sequences of buffalo CSN3.Among them,c.445GA,c.467CT and c.516AC changes were non-synonymous,which led to p.Val128Ile,p.Thr135Ile and p.Glu151Asp changes in κ-CN,respectively.And c.467CT and c.516AC may have an effect on the function ofκ-CN.Population genetic analysis revealed that allele c.445G、c.467C、c.471C and c.516A were preponderant alleles in river buffalo,whereas allele c.445G、c.467C and c.471C were preponderant alleles in swamp buffalo,and the genetic differences of CSN3 between river and swamp buffalo mainly embodied in the population genetic compositions of SNP516 site.