Deleting a Single Gene Promotes Massive Muscle Growth in Mice

Deleting a single gene creates a mighty mouse whose physiology could help scientists treat diseases such as muscular dystrophy or grow bigger farm animals, researchers report in the May 1 Nature. Se-jin Lee and colleagues at Johns Hopkins University in Baltimore said they had identified a gene that they called growth/differentiation factor-8 (GDF-8).

Mice genetically engineered to lack the gene grew enormous muscles, the researchers said. The mice were significantly larger than unaltered animals and showed a large and widespread increase in skeletal muscle mass. Individual muscles of mutant animals weighed two to three times more than those of normal mice.