Investigating the genetic polymorphism in the exon 2 region of ovine beta-lactoglobulin gene and its association with some milk traits

Abstract

beta-lactoglobulin (beta-LGB) gene is the major whey protein of ruminant and is synthesized by secreting cells of mammary gland during pregnancy and lactation and its biological function is still unclear. Therefore, the purpose of the study was to identify genotype frequencies of single nucleotide polymorphisms (SNPs) in ovine beta-LGB gene exon 2 region and its possible association with milk traits in dairy sheep breeds. The genetic structures of the SNPs were examined by PCR-RFLP and DNA sequencing in three sheep populations. A hundred fifty blood and milk samples each from Sakiz, Akkaraman and Awassi ewes, with total of 450 samples were used in the experiment. Awassi sheep breed was found as monomorphic for beta-LGB gene in exon 2 region. Genotype AB showed a strong association with milk yields content (P<0.001), whereas the animals carrying AA genotype had a higher fat percentage (P<0.001) value in the Sakiz sheep breeds. Furthermore, we have reported for the first time g. 121C>A SNPs of the beta-LGB gene for exon 2. In this research, beta-LGB showed a significant effect on milk yield in the Sakiz ewes, but further studies are necessary to confirm the association reported here.