Bos indicus type of growth hormone receptor gene is retained in Japanese Black cattle

The growth hormone receptor (GHR) gene is responsible for growth and carcass traits, and polymorphisms associated with the variation of meat production are thought to occur in the liver-specific promoter of the GHR gene in cattle. The aim of this study was to analyse the structure of the liver-specific promoter of GHR in Japanese Black cattle, as the relationship between GHR polymorphism and meat production is poorly understood in this breed. Typically in European cattle, the LINE-1 element, a family of retrotransposons, is inserted in the liver-specific promoter. However, a short GHR promoter without the LINE-1 sequence was found in the Japanese Black breed as in Bos indicus cattle. The frequency of the short allele was approximately 60%. In addition, 24 of 29 Holstein/Japanese Black crosses carried the short allele from their sire. The present result suggests that the short allele for GHR may be a candidate marker for improving meat production of Japanese Black cattle.