IGF2基因第2外显子多态性与牛生长性状相关性分析

Correlation between polymorphism in exon 2 of IGF2 gene and growth performance of cattle

【目的】探究IGF2第2外显子多态位点与秦川牛、西门塔尔牛、安格斯牛及新疆褐牛4种品种牛群体的多态性及与生长性状的相关性,为肉牛遗传改良提供依据。【方法】以秦川牛等4个肉牛品种共91头为研究对象,利用PCR-RFLPs技术分析IGF2基因第2外显子多态性,并将IGF2的基因型与生长性状进行相关分析。【结果】IGF2基因第2外显子多态性在不同牛品种中均处于Hardy-Weinberg平衡状态(P>0.05),且均属于中度多态(0.25<PIC<0.50)。IGF2基因第2外显子多态性与不同牛品种生长指标关联分析表明:秦川牛AA、AB基因型个体体重、体高、管围及尻宽显著优于安格斯牛、西门塔尔牛及新疆褐牛BB型个体(P<0.05);AA、AB型个体秦川牛和安格斯牛胸围显著优于西门塔尔牛及新疆褐牛(P<0.05);而腰角宽和胸深在各品种间差异不显著(P>0.05)。IGF2基因第2外显子多态性与不同月龄秦川牛生长性能相关性分析表明,AA、AB型个体12月龄体斜长显著高于BB型(P<0.05),其他月龄无显著差异(P>0.05);12、18月龄AA、AB型个体胸围显著优于BB型个体(P<0.05),其余各项指标基因型间差异不显著(P>0.05);在所有检测品种中,A为优势等位基因。【结论】研究表明IGF2基因第2外显子多态性与生长性能具有显著相关性,可作为肉牛生长性状辅助选择的标记之一,为优良肉牛早期选择提供参考依据。

【Objective】The present paper aimed to explore the polymorphism of IGF2 exon 2 polymorphism with Qinchuan cattle,Simmental cattle,Angus cattle and Xinjiang brown cattle population and its correlation with growth traits,so as to provide basis for genetic improvement of beef cattle.【Method】The polymorphism of IGF2 gene exon 2 was analyzed by PCR-RFLPs in 91 beef cattles of four breeds including Qinchuan cattle,and the association between IGF2 genotype and growth traits was analyzed.【Result】The polymorphism in exon 2 of IGF2 gene was in Hardy Weinberg equilibrium(P>0.05),and belonged to moderate polymorphism(0.25<PIC<0.50).The association analysis of IGF2 gene exon 2 polymorphism and growth indexes of different cattle breeds showed that the body weight,body height,tube circumference and rump width of Qinchuan cattle with AA and AB genotypes were significantly better than those of Angus,Simmental and Xinjiang Brown and BB genotypes(P<0.05);The chest circumference of Qinchuan cattle and Angus cattle with AA and AB genotypes was significantly better than that of Simmental and Xinjiang Brown(P<0.05).There was no significant difference in waist angle width and chest depth among the varieties(P>0.05).Correlation analysis between polymorphism of IGF2 gene exon 2 and growth performance of Qinchuan cattle at different months of age showed that body length of AA and AB individuals at 12 months of age was significantly higher than that of BB individuals(P<0.05),and there was no significant difference in other months of age(P<0.05);Chest circumference of AA and AB individuals at 12 and 18 months of age was significantly better than that of BB individuals(P<0.05),and there was no significant difference in other index genotypes(P>0.05);In all tested varieties,A was the dominant allele.【Conclusion】The results showed that the polymorphism in exon 2 of IGF2 gene had significant correlation with growth performance,which could be used as one of the markers for growth traits assistant selection of beef cattle and provide reference for early selection of excellent beef cattle.