The myostatin gene: an overview of mechanisms of action and its relevance to livestock animals.

Myostatin, also known as growth differentiation factor 8, a member of the transforming growth factor-beta super-family, is a negative regulator of muscle development. Myostatin acts at key points during pre- and post-natal life of amniotes that ultimately determine the overall muscle mass of an animal. Mutations have already demonstrated the impact of attenuating myostatin activity on muscle development. A number of large animals, including cattle, sheep, dogs and humans, display the 'double muscled' phenotype due to mutations in the myostatin gene. Here, we firstly give an overview of the molecular pathways regulated by myostatin that control muscle development. Then we describe the natural mutations and their associated phenotypes as well as the physiological influence of altering myostatin expression in livestock animals (cattle, sheep, goat, horse, pig, rabbit and chicken). Knowledge of null alleles and polymorphisms in the myostatin gene are of great interest in the animal breeding field, and it could be utilized to improve meat production in livestock animals.