Comparitive Genome Sequence Analysis of Bovine Lymphocyte Antigen BoLA DRB3.2 Alleles in Deoni and Ongole (Bos indicus) Cattle Breeds of India

Abstract

Background: India, a major livestock region of the Asian countries is rich in animal genetic resources having special qualities of hardy nature, resistance to many diseases and adopted to adverse climatic conditions. The cattle MHC, Bovine Lymphocyte Antigen DRB3 (BoLA-DRB3) is considered to be a major gene linked with disease resistance traits of Indian cattle. Methods: The present study was carried out to sequence the BoLA-DRB3.2 alleles in Deoni and Ongole breeds of Indian cattle. PCR RFLP analysis of the BoLA-DRB3.2 alleles in Deoni (n=51) and Ongole (n=60) cattle using three different restriction enzymes RsaI, BstYI and HaeIII to find out the possible restriction pattern. Based on the combined allelic patterns, each sample was further analyzed by PCR- SBT technique to detect the SNP variations present in BoLA-DRB3.2 alleles.Result: The PCR RFLP analysis revealed that the highest frequent alleles are *6 (0.216) and *15 (0.225) in Deoni and Ongole breeds of cattle, respectively. The second-highest frequency was observed for BoLA alleles *11 and *6 which were present at a frequency of 0.167 and 0.200 in Deoni and Ongole breeds of cattle, respectively. To get the complete picture of polymorphic pattern of BoLA-DRB3.2 allele direct sequencing was carried out for each plymorphic pattern. The interesting feature noticed in the Ongole breed was that at position 91 and 133 of the sequence, it had both A and G nucleotides in contrast to Bos taurus breed, which had only TT nucleotides. The sequence analysis of BoLA-DRB3 exon 2 between two breeds revealed that there are numerous variations in exon 2, whatever variation, that lead to different mobility shift and band pattern in gels. Deoni and Ongole breeds of cattle had similar variations at positions 94, 134, 211, 235 and 258noticed due to the unique nature of native breeds.