Haplotype C of growth hormone (GH) gene in Japanese Black cattle: Structure of GH protein and a novel method for detection of the gene

From a series of studies on single nucleotide polymorphisms (SNPs) in the bovine growth hormone (GH) gene of Japanese Black cattle, the type-C (127^Val and 172^Met) that is specific for this breed has been intensively focused upon because of the economic importance for carcass traits, such as intramuscular oleic acid contents. In the present study, we intended to analyze the 3-D structure of GH of haplotype C, and developed a novel method to detect the type C gene. Three-D analysis of the type C protein showed that the amino acid residues (127^Val and 172^Met), which are present in the third and fourth helixes, respectively, and are important for binding with GH receptors, are shifted to deeper positions in the molecule compared with that for type A (127^Leu and 172^Thr), implying the alteration of binding interaction with receptors. A novel, efficient and cost-effective method (Dot-blot-SNP technique) for type C genotyping was successfully established, of which the basal method was a reported genotyping of SNPs for a large number of plants, reducing the cost to 10% or less of direct sequencing.