Variation at MHC Class II-DQA locus in riverine and swamp buffaloes (Bubu) has been explored in this study. Through sequencing of buffalo DQA, 48 nucleotide variants identified from 17 individuals, reporting 42 novel alleles, including one pseudogene. Individual animal displayed two to seven variants, suggesting the presence of more than two Bubu-DQA loci, as an evidence of extensive duplication. dN values were found to be higher than dS values at peptide binding sites, separately for riverine and swamp buffaloes, indicating locus being under positive selection. Evolutionary analysis revealed numerous trans-species polymorphism with alleles from water buffalo assigned to at least three different loci (Bubu-DQA1, DQA2, DQA3). Alleles of both the sub-species intermixed within the cluster, showing convergent evolution of MHC alleles in bovines. The results thus suggest that both riverine and swamp buffaloes share con-current arrangement of DQA region, comparable to cattle in terms of copy number and population polymorphism.

本研究探索了河流和沼泽水牛 ( Bubu )中 MHC II- DQA基因座的变异。通过对水牛DQA 的测序，从 17 个个体中鉴定出 48 个核苷酸变异，报告了 42 个新的等位基因，包括一个假基因。单个动物表现出 2 到 7 个变异，表明存在超过两个Bubu - DQA基因座，作为广泛重复的证据。发现 dN 值高于肽结合位点的 dS 值，分别是河流和沼泽水牛，表明基因座处于正选择之下。进化分析揭示了许多跨物种多态性，其中来自水牛的等位基因被分配到至少三个不同的位点。Bubu - DQA1、DQA2、DQA3）。两个亚种的等位基因在簇内混合，显示牛中 MHC 等位基因的趋同进化。因此，结果表明河流和沼泽水牛共享DQA区域的并发排列，在拷贝数和种群多态性方面与牛相当。