Molecular characterization of genes involved in chicken MHC class I antigen presentation pathway

Tapasin, TAP1 and TAP2 are involved in the assembly of MHC class I molecules. The genes encoding these three products belong to the Major Histocompatibility Complex: in chicken, Tapasin is located between the two class IIb genes, while TAP1 and TAP2 are found between the two class I genes. The current study aimed at the molecular characterization of these three genes. Starting from Single Nucleotide Polymorphisms (11 in Tapasin, 18 in TAP1 and 21 in TAP2) previously discovered by the authors within these genes, the nucleotide diversity was assessed at each locus. Moreover, the haplotypes were reconstructed for each individual and the genetic distances between the chicken lines and breeds were estimated. From the analysis of the nucleotide diversity values, variable polymorphism rates could be observed among the three genes. In the three analyzed loci the SNPs rates were higher than the reported chicken genome mean nucleotide diversity of 5 SNPs kb(-1). The calculation of the genetic distances permitted, generally, the distinction of animals among the analyzed lines/breeds.