Delineating Genetic Variability: Comparative Analysis of Yak MHC-DQB Gene through cDNA Cloning

Nested within the vast genetic landscape of the major histocompatibility complex (MHC), a cluster of genes assumes a pivotal role in pathogen recognition and orchestrating mechanisms for disease resistance. This investigation successfully cloned and sequenced the complete 786 bp cDNA entity corresponding to the MHC-DQB gene in yaks. A comprehensive analysis of the sequence unveiled distinct features, including highly conserved peptide binding sites (PBS) spanning 8 amino acids and specific nucleotide-binding regions at designated positions (–1, –28, 2, 3, 29, 64, 93, and 108). The pronounced uniformity and remarkable preservation demonstrated by the yak MHC-DQB gene underscore its potential in providing protection against pathogens and the inherent stability within the DQB genetic framework. Moreover, a comparison across six distinct domains of the Yak-DQB gene revealed notable similarities with closely related species. Particularly significant is the identification of a conserved peptide-binding region consisting of 16 amino acids, alongside the detection of multiple conserved nucleotide-binding regions. When conducting a comparative analysis of amino acid lengths in the Yak-DQB orthologous sequence, a substantial homology with cattle was observed, registering at 91.2%. Interestingly, however, the DQB gene in yaks exhibited discrepancies in 23 amino acids compared to the bovine sequence. Specifically, a detailed examination revealed that 15 of these variable amino acids were clustered within the Beta 1 (в1) domain. These insights provide valuable information about the distinct characteristics of the MHC gene in both ruminant and non-ruminant species, unraveling the complexities of their comparative molecular genetics.