Genetic Variation And Expression Of Nramp1Gene And Its Associations With Chicken Immune Qualities

Nramp1(natural resistance associated macrophage protein1) is a siginificant candidate gene associated with Salmonella,Leishmania bacteria and BCG for genetic susceptibility to autoimmune diseases as well as infection.15chicken breeds were used for detecting SNPs in exon9of Nrampl gene using PCR-SSCP and sequencing methods.Some immune traits were detected in Rugao,Douji and Recessive White,and their relationship with SNPs were also analyzed.Simultaneously,the expression of different Nrampl genotypes in Rugao.The main results were as follows:1.PCR-SSCP method and DNA sequencing approach were used to identifying the single nucleotide polymorphisms(SNPs)of Nrampl gene,and5mutations which was C242A、 C315G、C357T、G419T、C427T were found.The Heterozygosity of15chicken breeds(expect Luyuan) was between0.382and0.5,and the PIC was almost0.35.2.Some immune traits were detected in Rugao,Douji and Recessive White.The results showed that Bursa index of RG was largest at8weeks,Thymus index of RG reached the maximum at8weeks,Spleen index of RG was biggest at6weeks.Lymphocyte transformation rate of RG increased with age.The content of IgM and IgG of RG decreased with age.H/L value of RG was significantly lower than RW and DJ(P<0.05).Lymphocyte transformation rate of RG was significantly higher than RW and DJ(P<0.05).The content of IgM and IgG of DJ were significantly higher than RG and RW(P<0.05), the content of IgM and IgG of RG was significantly higher than RW(P<0.05). The general immune performances of Chinese native chicken breeds were superior to those of exotic breeds.3.The correlation between the polymorphisms of Nramp1gene and immune traits showed that H/L value of AA genotype was significantly lower than that of BB genotype and AB genotype, while the AA genotype’s lymphocyte transformation rate and IgM were significantly higher than BB genotype’s in RG.RW and DJ. The general immune performance of AA genotype in three chicken breeds were superior to those of the other two genotypes.4.Analysis of the correlation between the three genotypes and some commercial traits showed that all commercial traits among the three genotypes expect the weight of abdominal fat were not significantly different in Rugao chicken(P>0.05).It showed that there was no obvious negative correlation between immune traits and economic traits in genotypes.AA genotype may be a new disease-resistant genotypes..5.The Nrampl gene expression was observed in all tissues and no tissue specific expression.Nramp1gene performed highly specific expression in RG thymus, heart and liver,while the expression of thymus and bursa was basically the same.The Nrampl gene expression of thymus is significantly higher than bursa(P<0.05). The Nramp1gene expression of heart and liver was higher in0week,while the Nrampl gene expression of thymus and bursa was higher in6week.There is no significant difference in the Nrampl gene expression of different genotype in the same tissue(P>0.05). But the mean of AA genotype is highest in the3genotypes,it maybe correlate with the best immune traits.