A variation of simple repeat sequence in the promoter region of the bovine growth hormone (bGH) gene in beef cattle is similar to water buffalo

A simple repeat sequence variation (AAG repeat) was detested in the promoter region of the bovine growth hormone (bGH) gene upstream the TATA box. The G(1) allele with only one AAG repeat and the G(2) allele with two AAG repeats were observed in the beef breeds Nelore, Guzerat and Chianina. In the dairy breeds Gyr, Holstein and Brown Swiss only the G(2) allele was present. Gene frequency for the G(2) allele was 0.144 in Nelore, 0.10 in Guzerat and 0.091 in Chianina. Heterozygous individuals can be identified by the presence of heteroduplex bands on polyacrylamide gels. Sequence analysis further revealed that the G(1) allele is identical to the water buffalo GH gene promoter region. It has not yet been established whether variants in the promoter region have any effect on the level of transcription of the bGH gene.