六个鸡种IGFBP-3基因第2外显子MspⅠ酶切位点的遗传多态性研究

Polymorphisms of MspⅠLocus at Exon 2 of IGFBP-3 Gene in Six Chicken Breeds

采用PCR-RFLP和DNA测序技术,研究京海黄鸡、AA鸡、尤溪麻鸡、如皋草鸡、鹿苑鸡、边鸡6个品种IGFBP-3基因第2外显子MspⅠ位点的多态性。结果显示,IGFBP-3基因第2外显子1087bp处有C→T的突变,鸡群体中表现出AA、AB和BB3种基因型。3种基因型在6个鸡品种间分布趋势一致:AA为优势基因型,BB为劣势基因型。经χ2适合性检验,除京海黄鸡外其余5个品种的MspⅠ位点均处在Hardy-Weinberg平衡状态(P>0.05)。群体遗传分析表明,AA鸡纯合度最高,京海黄鸡纯合度最低。6个鸡品种MspⅠ位点为中度多态。京海黄鸡有效等位基因数最多,为1.900,AA鸡有效等位基因数最少,为1.471。表明鸡IGFBP-3基因在不同品种中具有丰富的单核苷酸多态性,可以进一步作为候选基因来分析其与生长性状的相关性。

PCR-RFLP and DNA sequencing were used to detect MspⅠ polymorphism at exon 2 of IGFBP-3 gene in Jinghai yellow chicken,AA chicken,Youxi chicken,Rugao chicken,Luyuan chicken,Bian chicken.The results showed that a C→T mutation was happened in 1087 bp loci at exon 2 of IGFBP-3 gene.Three genotypes（AA,AB,BB） were detected in the six chicken breeds.All three genotypes showed the same distribution among six breeds,AA was the highest and BB was the lowest.χ2 analysis showed that distribution of the three genotypes was very different among different breeds（P0.01）.Except for the Jinghai yellow chicken,all the other five breeds were in accordance with the Hardy-Weinberg equilibrium.Genetic analysis indicated that homozygosity was the highest in the AA chicken,lowest in the Jinghai yellow chicken.Polymorphism information content（PIC） was intermediate in all six breeds.Effective number of alleles was the highest in the Jinghai yellow chicken（1.900）,the lowest in the AA chicken（1.471）.These results showed that IGFBP-3 gene had a medium level of polymorphism in different chicken breeds,and could be used as a candidate gene to analyze the correlation between its polymorphism and growth traits in chicken.