Abstract: The invention relates to a gene (cDNA) encoding a bovine myostatin protein. The nucleic acid coding sequence is identified as SEQ ID NO:1 and the protein sequence is identified as SEQ ID NO:2. A mutant gene (SEQ ID NO:3) in which the coding sequence lacks an 11-base pair consecutive sequence (SEQ ID NO:11) of the sequence encoding bovine protein having myostatin has been sequenced. It has been shown that cattle of the Belgian Blue breed homozygous for the mutant gene lacking myostatin activity are double-muscled. A method for determining the presence of muscular hyperplasia in a mammal is described. The method includes obtaining a sample of material containing DNA from the mammal and ascertaining whether a sequence of the DNA encoding (a) a protein having the biological activity of myostatin, is present and whether a sequence of the DNA encoding (b) an allelic protein lacking the activity of (a), is present.

Abstract: The invention relates to a gene (CDNA) encoding a bovine myostatin protein. The nucleic acid coding sequence is identified as SEQ ID NO:1 and the protein sequence is identified as SEQ ID NO:2. A mutant gene (SEQ ID NO:3) in which the coding sequence lacks an 11-base pair consecutive sequence (SEQ ID NO:11) of the sequence encoding bovine protein having myostatin has been sequenced. It has been shown that cattle of the Belgian Blue breed homozygous for the mutant gene lacking myostatin activity are double-muscled. A method for determining the presence of muscular hyperplasia in a mammal is described. The method includes obtaining a sample of material containing DNA from the mammal and ascertaining whether a sequence of the DNA encoding (a) a protein having the biological activity of myostatin, is present and whether a sequence of the DNA encoding (b) an allelic protein lacking the activity of (a), is present.

Abstract: The present invention involves carrying out a gene targeting method utilizing the cre-lox system in order to generate transgenic mice allowing for conditional inactivation of the myostatin gene. The transgenic mice of the present invention that express a conditionally inactivated myostatin gene also exhibit a phenotype characterized by skeletal muscle hypertrophy.