欣华鸡DRD2基因多态性及其与蛋用性状的关联分析

试验旨在研究多巴胺受体D2(dopamine receptor D2,DRD2)基因多态性及其与欣华鸡蛋用性状的相关性,寻找可用于欣华鸡蛋用性状选育的分子遗传标记。应用Primer Premier 5.0软件设计4对引物,利用PCR-RFLP技术对欣华E系鸡群的473个个体进行基因型鉴定,使用SPSS 19.0软件将欣华鸡的蛋用性状与DRD2基因多态性进行关联分析。群体多态性分析结果表明,存在4个SNPs位点:A-16105G(SNP1)、G-12510T(SNP2)、G+3360A(SNP3)和T+5042C(SNP4),其中SNP1和SNP2位点符合哈代-温伯格平衡(P>0.05),且杂合度较低,但SNP3和SNP4位点显著偏离哈代-温伯格平衡(P<0.05)。关联分析表明,DRD2基因4个SNPs位点与欣华E系鸡群体蛋用性状存在关联,其中与产蛋性状关联结果:SNP1与开产日龄显著关联(P<0.05),SNP2与33周龄产蛋数、300日龄产蛋总数极显著关联(P<0.01),SNP3与开产体重(P<0.05)、300日龄产蛋总数(P<0.01)、平均连产(P<0.01)和最长连产(P<0.05)关联,SNP4与开产日龄极显著关联(P<0.01);与蛋品质关联结果:SNP1与蛋形指数(P<0.01)、蛋黄颜色(P<0.01)和哈氏单位(P<0.05)关联,SNP2与蛋黄重显著关联(P<0.05),SNP3与蛋壳强度极显著关联(P<0.01),SNP4与蛋黄重、蛋清重和哈氏单位显著关联(P<0.05)。单倍型分析发现,DRD2基因4个SNPs位点的不同单倍型组合与欣华鸡的最长连产长度呈极显著相关(P<0.01),与哈氏单位呈显著相关(P<0.05)。组织表达谱分析发现,DRD2基因主要在欣华E系鸡垂体中表达,在58周龄鸡胸肌中有较高表达,在36周龄鸡脑中有少量表达。结果表明,DRD2基因可作为候选基因辅助用于欣华E系鸡群体蛋用性状的遗传改良。

Polymorphism of DRD2 Gene and Its Associations with Egg Traits in Xinhua Chicken

This study was aimed to investigate the polymorphism of dopamine receptor D2 (DRD2) gene and its correlation with egg traits in Xinhua chicken,and find the molecular genetic markers for the breeding of egg traits in Xinhua chicken.4 pairs of primers were designed using Primer Premier 5.0,the genotype of 473 individuals in Xinhua E-line chicken were identified by PCR-RFLP method,the correlation were analyzed between egg traits of Xinhua chicken and polymorphism of DRD2 gene using SPSS 19.0 software.Population polymorphism analysis results showed that there were 4 SNPs of A-16105G (SNP1),G-12510T (SNP2),G+3360A(SNP3) and T+5042C(SNP4),SNP1 and SNP2 were in Hardy-Weinberg equilibrium (P>0.05),and the heterozygosity were low,SNP3 and SNP4 significantly deviated from the Hardy-Weinberg equilibrium (P<0.05).Correlation analysis results showed that 4 SNPs of DRD2 gene were associated with egg traits in Xinhua E-line chicken,for egg production traits,SNP1 was significantly associated with age at the first egg (P<0.05);SNP2 was extremely significantly associated with egg production at 33 weeks old and the total number of eggs at 300 days of age (P<0.01);SNP3 was associated with body weight at sexual maturity (P<0.05),the total number of eggs at 300 days of age (P<0.01),average clucth size (P<0.01) and the largest clucth size (P<0.05);SNP4 was extremely significantly associated with age at the first egg (P<0.01).For egg quality traits,SNP1 was associated with egg-shaped index (P<0.01),yolk color (P<0.01) and Haugh units (P<0.05);SNP2 was associated with yolk weight (P<0.05);SNP3 was extremely significantly associated with eggshell strength (P<0.01);SNP4 was significantly associated with yolk weight,albumen weight and Haugh units (P<0.05).The haplotype analysis results showed that the different haplotype combinations of 4 SNPs of DRD2 gene were significantly correlated with the longest clutch size in chicken (P<0.01) and haugh units of eggs (P<0.05).The tissue expression profiling results indicated that DRD2 gene was mainly expressed of pituitary gland in Xinhua chicken,and was also highly expressed in chest muscle at 58 weeks old,with a low expression in brain at 36 weeks old.The results suggested that DRD2 gene in Xinhua E-line chicken could be used to assist the genetic improvement of egg traits.