Characterization of BoLA class II DQA and DQB by PCR-RFLP, cloning, and sequencing reveals sequence diversity in crossbred cattle

The BoLA class II DQA and DQB genes in crossbred cattle were studied using PCR-RFLP, cloning, and sequencing techniques. Seventy-two crossbred cattle ( Vrindavani ) were used in the current study. Hae III and Xba I restriction enzymes digested DQA exon 2-3, revealing seven ( Hae III-A-G) and three ( Xba I A-C) motifs, respectively. The BoLA- DQB gene was analyzed using PCR-RFLP with Pst I and Taq I restriction enzymes, yielding five restriction motifs for each restriction enzyme ( Pst I-A-E and Taq I-A-E). In crossbred cattle, addition, deletion, and substitutions were observed in distinct sequences, resulting in variations in overall gene length. Changes in nucleotides at positions 64–80, 110–200, and 207–264 were largely responsible for polymorphism in DQA exon 2. The phylogenetic analysis predicted a high degree of nucleotide and amino acid changes in DQA exon 2-3 and DQB exon 2. DQA genes had a nucleotide dissimilarity of 0.3–25.4 percent, while DQB genes had a nucleotide dissimilarity of 1.5–14.3 percent. We cloned and sequenced 20 genotypes based on PCR-RFLP of the DQA and DQB genes. The current study observed variation in the DQA and DQB genes and will serve as a foundation for future research on the BoLA DQA and DQB genes.