Genetic Variance Analysis Of The MHC B-L Gene In Different Chicken Breed And Its Association With Immune Traits

The chicken major histocompatibility complex (MHC) is located on chromosome 16, which is essential in the presentation of antigens.In recent years, the crucial character of the MHC in Polymorphism, linkage disequilibrium and haplotype heredity therefore makes this a promising candidate region for research.This study was performed using 11 breeds birds from nine Chinese indigenous chicken breeds and two overseas Chicken Breeds, the PCR-SBT method was applied to found SNP in exon 2 of the MHC B-L gene. The genetic diversity in indigenous chicken breeds and the genetic variation between Chinese indigenous chicken breeds and overseas Chicken were analysed, furthermore, the genotype of variation loci and association of SNPs in exon 2 of the MHC B-L gene with immune traits in White Leghorn were investigated and analyzed using the identified haplotypes. The results showed that:84 SNP were detected in 267bp DNA of nine Chinese indigenous chicken breeds, this study has clearly shown that high variability and high genetic potential was included in MHC B-L exon2 gene. The results of phylogenetic relationship showed the genetic distance were longest between Beijing-you chicken and Xianju chicken, the genetic distance were most close between silk chicken and Xianju chicken.The comparison of sequence polymorphisms for MHC B-L exon2 gene in indigenous chicken breeds showed that high variability was found in the sequences of MHC.43 SNP and 37 SNP were detected in Leghorn chickens and Recessive White Feather Broiler separaterly. Comparison of sequence polymorphisms for MHC B-L exon2 gene between indigenous chicken breeds and overseas chicken breeds showed the all SNP of overseas chicken were included in indigenous chicken breeds, the specific SNP in indigenous chicken breeds were 26. The common SNP in overseas chicken breeds is 26, the variation leaded to the change of 22 amino acid, the amino acid is located onβ1 region of MHC molecule..Association of 37 SNPs in exon with immune traits was analyzed. Of 37 SNPs detected from all 500 individuals in 25 sire.Association of 5 SNPs in exon with IgG of blood serum was analyzed, Of 16 haplotypes detected from all individuals;1 SNP was associated with LPS of blood serum;11 SNPs were associated with serum antibody against AI. 61 haplotypes were detected; Antibody against ND was associated with 18 SNPs 116 haplotypes were detected;Hemagglutinating antibodies against SRBC were associated with 6 SNP Of the total of 21haplotypes detected from all individuals.