A deletion in the bovine myostatin gene causes the double-muscled phenotype in cattle.
In Belgian Blue cattle, segregation analysis performed in experimental crosses and in the outbred population has suggested autosomal recessive inheritance of double muscling. In the present work this was confirmed when the muscular hypertrophy (mh) locus was mapped 3.1 cM from microsatellite TGLA44 on the centromeric end of chromosome 2. A positional candidate approach was used to demonstrate that a mutation in bovine MSTN, which encodes myostatin, a member of the TGFβ superfamily, was responsible for the double-muscled phenotype. It was concluded that an 11 bp deletion in the coding sequence for the bioactive carboxy-terminal domain of the protein causes the muscular hypertrophy observed in Belgian Blue cattle.