Study on the association of BoLA-DRB3.2 alleles with clinical mastitis in Iranian Holstein and Sarabi (Iranian native) cattle

Abstract

Seventy-five Iranian Holstein cattle which comprised of two different groups (49 susceptible cattle to clinical mastitis and 26 resistant cattle to clinical mastitis) as well as forty-five Sarabi breed cattle were studied randomly for polymorphism in BoLA-DRB3.2 gene. Genotyping by single strand conformation polymorphism- polymerase chain reaction (SSCP-PCR) and then sequencing revealed the presence of previously reported 13 alleles of BoLA-DRB3.2 gene across both studied breeds. However, 3 new alleles
were identified for the studied gene in Sarabi breed in addition to the 13 alleles. Cloning and sequencing of the three newly found alleles in this study confirmed their novelty (NCBI Genebank accession numbers, EU362974, EU372975 and EU372976). Multi-primer target polymerase chain reaction (MPT-PCR) in this study failed to accurately differentiate the resistant and susceptible cattle to clinical mastitis. A combination of single strand conformation polymorphism (SSCP) and heteroduplex analysis (HA) in a non-denaturing gel, successfully detected the resistant genotype to clinical mastitis (DRB3.2*16). To the best of our knowledge, this is a pioneer study on the BoLA-DRB3.2 gene across an Iranian native breed (Sarabi). The results demonstrated that the BoLA-DRB3.2 locus is highly
polymorphic in the Sarabi cattle.