Abstract: Transporter associated with antigen processing (TAP) genes are located in the major histocompatibility complex (MHC) region, and the dimers composed of TAP1 and TAP2 can transport the antigen peptide from cytoplasm into the endoplasmic reticulum cavity. Therefore, they play an important presentative role in an immune response. [Objective]To further reveal the effect of varied SNPs in TAP2 genes on their proteins structure, and to characterize their genetic variation in different chicken breeds. [Method]Target capture sequencing assay was used to determine the full length of TAP2 genes in 260 chicken individuals of 26 breeds. The multiple sequence alignment analysis among the obtained sequences of 26 chicken breeds was carried out using DNAMAN software to screen the locations and to determine the types of the SNPs in TAP2 genes in 26 chicken breeds. The impact of the SNPs in TAP2 genes on their corresponding proteins structure was predicted via bioinformatics software. The phylogenetic tree was established to assess the homology of TAP2 genes among different chicken breeds. [Result]The effective sequencing length of TAP2 gene was 3 037 bp. A total of 20 SNPs were observed in the 26 different chicken breeds, indicating a rich genetic diversity. Among them, 9 were found in exons and the remaining ones were located in introns. The effect of four SNPs (rs316795220, rs738706078, rs739725385 and rs732937653) on structure of the proteins encoded by them was characterized. [Conclusion]The TAP2 gene in chicken has rich genetic diversity, providing abundant original materials for further application of these germplasm resources of chickens. Our results give new insights into the studies on selection of candidate SNPs in TAP2 gene involved in antibody transportation function.

Key words: chicken, TAP2, SNP, resistance