猪Mx1基因第14外显子多态性分析及新突变位点的 发现

采用PCR-RFLP方法对国内外7个猪种Mx1基因第14外显子的多态性进行分析, 共检测到3个等位基因, 6种基因型。其中杜洛克中仅存在AA基因型, 苏太猪中存在全部基因型, 只有在梅山猪和具有梅山猪血统的苏太猪中出现基因型BB。所有猪种中, 只有在地方猪种和培育猪种中出现等位基因B, 所有猪种除松辽黑猪外均以A为优势等位基因。卡方检验结果表明, 不同猪种间基因型分布差异较大, 梅山猪和松辽黑猪与其他所有猪种的基因型频率差异极显著(P＜0.01) , 苏太猪与除皮特兰猪外的所有猪种的基因型频率差异也极显著(P＜0.01) , 淮猪与杜洛克和约克夏这两个国外猪种基因型频率差异不显著(P＞0.05), 而与皮特兰和其他地方猪种的基因型频率均存在极显著差异(P＜0.01) 。通过测序在扩增片段中新发现了3种类型的碱基突变, 前2个分别导致了Thr和Glu向Ala和Arg的替换, 最后一个突变不引起氨基酸的变化, 且后两个突变位点为BB基因型所特有。

Analysis of polymorphisms in exon 14 in porcine Mx1 gene and iden-tification of new mutation points

By the PCR-RFLP method, the polymorphisms of exon 14 of Mx1 gene were detected in 7 native and foreign pig breeds. Taken together with the analysis of restriction enzyme Hin6 I digestion, there were 6 genotypes and 3 alleles. And, all individuals of Duroc exhibited the AA genotype but the Sutai pigs exhibited all three kinds of genotypes. The BB genotype was detected only in Meishan pigs and their derivate Sutai pigs. Among all pig breeds, the allele B only appeared in Chinese indigenous pig breeds and developed pig breed in this study, and the allele A was dominant allele in all pig breeds except for Songliao black pig. The results of Chi Square test showed that there were abundant polymorphisms in all pig breeds. The gene frequency of Meishan pig and Songliao black pig showed greatly significant difference to other pig breeds (P<0.01), Sutai pig showed greatly significant difference (P<0.01) to other pig breeds except for Pietrain; and Huai pig showed greatly significant differences (P<0.01) with Pietrain and other indigenous Chinese pig breeds, but no difference with Duroc and Yorkshire (P>0.05). Three new mutation points in three genotypes were identified by sequencing comparison analysis of PCR products, two of which resulted in Thr-->Ala and Glu-->Arg respectively, the last one was a silence mutation, the Glu-->Arg mutation point and this silence mutation point only appeared in the individuals with the BB genotype.