MHC-DRB1 exon 2 polymorphism and its association with faecal egg count of Haemonchus contortus in Munjal sheep

Abstract

Haemonchosis is an important disease of small ruminants. Anthelmenthic resistance has instigated the demand of other viable method for control of gastrointestinal parasite. Here, we investigated ovine major histocompatibility complex class II (Ovar MHC II) DRB1 exon 2 polymorphism and its association with faecal egg count (FEC) of Haemonchus contortus in Munjal population of sheep. Genomic DNA was isolated from blood samples of 46 lambs between 6-7 months of age. The polymorphism in DRB1 gene was analyzed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. PCR products of exon 2 of DRB1 gene were digested with HaeII, BsaHI and NciI restriction enzymes. Fragment of the DRB1 gene comprising 9 bp of the 5' intron and 270 bp of entire exon 2 was successfully amplified. On digestion of 279 bp PCR product with NciI, three genotypes viz. A1A1, A2A2 and A1A2 were found with allele frequencies 0.65 and 0.35. HaeII enzyme revealed three genotypes A1A1, A1A2 and A2A2 with allele frequencies of A1 and A2 were 0.42 and 0.58. BsaHI enzyme also generated three genotypes A1A1, A1A2 and A2A2 with allele frequencies of A1 and A2 was 0.42 and 0.58. We were able to found polymorphism in DRB1 gene but no association could be established between genotypes generated by different restriction enzymes and FEC of H. contortus in Munjal sheep.