In postnatal life, growth and repair of skeletal muscle fibers are mediated by the satellite cells. These cells divide at a slow rate to sustain both self-renewal and growth of skeletal muscle tissue. In response to muscle injury, satellite cells divide and fuse to repair or replace the damaged muscular fibers. However, the self-renewal potential of adult satellite cells is limited and is compromised with aging, excessive trauma, or genetic defect as in certain severe muscular dystrophies such as Duchenne muscular dystrophy. In such cases, external interventions are needed. UC Berkeley researchers have developed a chemical cocktail that allows large number of myogenic stem cells to be derived from, but no limited to, mouse dermal fibroblasts. These myogenic stem cells could then be transplanted into diseased or injured skeletal muscle to promote regeneration and recovery. In addition, the chemicals could be directly delivered into diseased or injured skeletal muscle to promote regeneration in vivo. The mixture allows large number of patient-specific skeletal muscle cells to be obtained conveniently from non-invasive skin biopsy techniques. The in vitro culture of these skeletal muscle cells can then be used for disease modeling and drug screening purposes.