Myostatin (or GDF-8) is a member of the TGF-beta superfamily, which has been associated with carcass traits in beef breeds. Six polymorphisms within exons 2 and 3 of the cattle myostatin sequence results in a "loss of function" that give rise to a hyperplasia of skeletal muscle in a phenotype known as 'double muscling' (mh). As with beef producing breeds, goat meat breeds such as the South African Boer goat were selected on the basis of superior growth characteristics and carcass traits. The study was aimed at identifying polymorphisms found in the goat myostatin sequence. PCR and sequencing primers were designed for the goat based on information from nucleotide sequences of cattle myostatin in GenBank. The six polymorphisms that give rise to double muscling in cattle were not detected in the goat sequence. However, 38 nucleotide differences are described between the myostatin sequences in cattle and that of the goat. There were 25 non-synonymous changes and 13 synonymous changes. The ability to type for these polymorphisms provides an opportunity to assess further mutation in ruminants. (C) 2003 Published by Elsevier B.V.