Variations in MHC-DRB1 exon2 and associations with Brucellosis susceptibility in Chinese Merino sheep

Abstract

The aim of this study was to investigated the association between MHC-DRB1 exon2 and Brucellosis susceptibility in Chinese Merino sheep. MHC-DRB1 exon2 was amplified by polymerase chain reaction (PCR) from 126 healthy and 67 Brucellosis-infected Chinese Merino sheep. PCR products were analyzed using the SSCP technique, and then cloned to allow sequencing of the different alleles. For each SNP, allelic and genotypic frequencies were compared between case and control samples, in addition the association with Brucellosis susceptibility was determined. Haplotypes and their frequencies were established and analyzed by SHEsis online software. There were forty-one single nucleotide polymorphisms (SNPs) in the 270 bp DNA sequence. The distribution of C>T alleles at locus 109 was significantly different between case and control samples. The linkage disequilibrium (LD) analysis showed that there were nine LD blocks in MHC-DRB1 exon2 and strong LD between SNPs existed in every Block. Haplotype analysis identified nine haplotypes with strong LD, but only Hap8 and Hap9 in case-control groups were significantly different (PT allele at locus 109. In conclusion, genetic variants of MHC-DRB1 gene exon2 demonstrated associations with Brucellosis susceptibility, indicating that further research is warranted.\n\nAbbreviations