中国地方牛CCK基因第1外显子的多态性及其与生产性状的相关性

Polymorphism of exon 1 in CCK gene assocated with growth traits of Chinese native cattle

【目的】研究中国本地牛胆囊收缩素(Cholecystokinin,CCK)基因第1外显子的多态性及其与南阳牛生产性状的关系,为中国地方牛品种的选育提供参考。【方法】利用PCR-RFLP和DNA测序技术,研究了6个中国本地牛品种(南阳牛、秦川牛、郏县红牛、鲁西牛、草原红牛和荷斯坦奶牛)1390头个体CCK基因的多态性,并分析其多态性与南阳牛生产性状的相关性。【结果】DNA池测序结果发现,CCK基因第1外显子有2个新的SNP多态位点(1 224 T→C,1 275 G→C),其中1 275 G→C是一个错义突变,该突变导致1个内切酶PVUⅡ切割位点的消失,表现为GG、GC、CC 3种基因型。3种基因型在南阳牛、秦川牛、郏县红牛、鲁西牛、草原红牛和荷斯坦奶牛CCK基因第1外显子G等位基因的频率分别为0.744 0,0.947 0,0.888 5,0.956 3,0.756 3,0.957 0;C等位基因频率分别为0.256 0,0.053 0,0.111 5,0.043 7,0.243 7,0.043 0。不同基因型与南阳牛生产性状的相关分析表明,GC和CC基因型个体除了与初生质量和6月龄性状指标不相关外,与12,18,24月龄体质量、体长、平均日增质量和胸围性状均存在显著或极显著相关。【结论】CCK基因可能是影响牛生产性状的主效基因或者与之紧密连锁,可能是牛分子育种的候选基因之一。

【Objective】 The study was to study the polymorphism of the missense mutation in exon 1 of CCK gene and the association with the production traits in Nanyang cattle,in order to provide reference for the breeding of Chinese local cattle.【Method】 DNA sequencing and PCR-RFLP were applied to analyze the polymorphism of CCK gene in 1390 individuals that comprised six Chinese native cattle（Nanyang cattle,Qinchuan cattle,Jiaxian Red cattle,Luxi cattle,Caoyuan Red cattle and Holstien cow）,and associated with the growth traits in Nanyang group.【Result】 DNA pool sequencing found that two novel mutations 1 224 T→C,1 275 G→C in exon 1 of cholecystokinin gene were identified,and 1 275 G→C was a novel missense mutation of CCK gene,the mutation caused the disappearance of the natural enzymes site of PVUⅡ,and created three genotypies GG,GC and CC.Moreover,the frequencies of alleles G/C of Nanyang cattle,Qinchuan cattle,Jiaxian Red cattle,Luxi cattle,Caoyuan Red cattle and Holstien cow populations were 0.744 0/0.256 0,0.947 0/0.053 0,0.888 5/0.111 5,0.956 3/0.043 7,0.756 3/0.243 7,0.957 0/0.043 0.Then the associations between different genotypies with the growth traits of Nanyang cattle were analyzed,indicating that： except birth weight and 6 months age showed unrelation,there were relation in body weight,body length,average day gain and heart girth of the individuals in 12 months,18 months,24 months,significantly or extremly significant in Nanyang breed.【Conclution】 CCK gene seems to be promising candidate for a genetic marker as it plays an important role in cattle＇s growth traits,or linked with it,and CCK gene might be one of candidators of breeding.