贵州地方鸡IL8RB基因多态性及其对肉品质的影响

Polymorphism of the IL8RB gene in 3 Guizhou local chicken and its effect on meat quality

为了挖掘IL8RB基因的单核苷酸多态性(SNP)位点,以长顺绿壳蛋鸡、黔画乌鸡和威宁鸡为材料,采用PCR产物直接测序法对IL8RB基因进行SNP筛查,对突变前后序列进行生物信息学分析.结果表明:在3个鸡群体IL8RB基因中共检测到2个错义突变位点,g.22589443 C>T突变共产生3种基因型,为中度多态,引起亮氨酸变成丝氨酸;g.22589512 C>T突变共产生2种基因型,为低度多态,引起苏氨酸变成甲硫氨酸.卡方(χ^2)检测结果表明:g.22589443 C>T位点在长顺绿壳蛋鸡群体的基因型分布极显著偏离了Hardy-Weinberg平衡(P<0.01),在黔画乌鸡和威宁鸡群体基因型分布显著偏离了Hardy-Weinberg平衡(P<0.05);g.22589512 C>T突变位点在3个鸡群体基因型分布未偏离Hardy-Weinberg平衡(P>0.05).连锁不平衡分析结果显示:3个鸡群体IL8RB基因2个SNP位点间不存在强连锁不平衡;2个SNP位点联合共产生3种单倍型和4种双倍型,单倍型H1和双倍型H1H1出现的频率最高,单倍型H3和双倍型H2H2出现的频率最低.生物信息学分析表明:3种单倍型自由能为:TC>CC>CT,稳定性为:CT>CC>TC;2个SNP位点引起氨基酸变化但未引起蛋白质二级结构和三级结构变化.IL8RB基因变异与黔画乌鸡肉品质关联性分析发现,双倍型H1H1个体的肉色指标显著高于H1H3个体(P<0.05),其他各SNP位点及双倍型在各指标之间的差异未达到显著水平(P>0.05).所检测到的这2个SNP位点或许可作为改善鸡肉品质遗传标记,为今后深入研究提供数据参考和理论支持.

In order to excavate the single nucleotide polymorphism(SNP)site of the IL8RB gene,SNP screening was performed on the IL8RB gene by direct sequencing PCR products of Changshun blue-eggshell chicken,Qianhua black-bone chicken and Weining chicken,and sequences before and after mutation were analyzed by bioinformatics.The results showed that 2 missense mutation sites were detected in the IL8RB genes of 3 chicken populations.G.22589443 C>T mutation produced 3 moderately polymorphic genotypes,causing leucine to become serine,while g.22589512 C>T mutation generated 2 genotypes with low polymorphisms,which caused threonine to become methionine.Chi-square test results showed that the genotypic distribution of g.22589443 C>T in Changshun green-shell hen population highly significantly deviated from the Hardy-Weinberg equilibrium(P<0.01),and that of black-bone chicken and Weining chicken significantly deviated from Hardy-Weinberg equilibrium(P<0.05),while g.22589512 C>T mutation site did not deviate from the Hardy-Weinberg equilibrium in 3 chicken populations(P>0.05).Linkage disequilibrium analysis revealed that there was no strong linkage disequilibrium between the 2 SNP loci of the IL8RB gene for the 3 chicken populations.Two haplotypes and 4 diplotype were co-produced by the 2 SNP sites,with the highest frequency coming from haplotype H1 and diplotype H1H1,and the lowest frequency coming from haplotype H3 and diplotype H2H2.Bioinformatics analysis found that the free energy of the 3 haplotypes were TC,CC and CT in a descending order with the stability following the opposite order of the free energy.Two SNP sites gave rise to amino acid changes but did not cause protein secondary and tertiary sstructural changes.Correlation analysis on the IL8RB gene mutations and meat quality of Qianhua black-bone chicken showed that the meat color index of diplotype H1H1 individuals was significantly higher than that of H1H3 individuals(P<0.05),while other SNP loci and diplotypes did not differ between the indicators tested(P>0.05).Therefore,g.22589443 C>T and g.22589512 C>T may serve as genetic markers for improving chicken quality,providing data references and theoretical support for further research.