Abstract: DMA (major histocompatibility complex, class Ⅱ, DM alpha) is a typical gene of chicken MHC class Ⅱ, which is closely related to the host immune response and disease resistance. In this study, we detected DMA gene of 25 different chicken breeds by target capture sequencing and used DMA gene sequence of Gallus gallus in NCBI as the reference. Then we analyzed gene sequence by MEGA6, screened SNPs (single nucleotide polymorphism) and Indels (insertion-deletion) of DMA gene sequences in different chicken breeds. Finally, we constructed the phylogenetic tree according to the differences in gene sequences. The results revealed that the DMA gene appeared rich polymorphism. SNPs and Indels were concentrated on exons mostly. Meanwhile, base deletions on exon2 caused the great changes in its translated products. In addition, the phylogenetic tree showed the chickens with better disease resistance such as Tibetan chicken and game chicken had high homology. The above results demonstrated that the DMA gene is rich in genetic diversity which is related to the differences in innate immunity and disease resistance in chicken breeds. The Indels in exon 2 94 496-94 552 can be used as a candidate marker of chicken immune characteristics.

Key words: chicken, DMA gene, MHC, SNPs, Indels, phylogenetic tree