Developmental genetics of a lethal mutation, muscular dysgenesis ( mdg), in the mouse : I. Genetic analysis and gross morphology

A new lethal mutation in the mouse designated muscular dysgenesis ( mdg) was found to be transmitted as a single autosomal recessive gene. The most striking effect in newborn mice homozygous for the mdg mutation is a severe, general deficiency of skeletal musculature; cardiac and smooth muscles appear normal. The deficiency appears to be the result of a genetically determined abnormality of muscle cell differentiation. Various other abnormalities of the mdg syndrome are described which appear to be the result of skeletal muscle deficiency. The potential value of this mutation for studies of muscle cell differentiation and for the investigation of the interaction between skeletal musculature and other systems during development is discussed.