ABOVE: In patients with muscular dystrophy, muscle fibers (purple) are replaced by adipose tissue (black) as muscles waste away and lose function. (Mesenchymal tissue shown in green and yellow.)
© PATRICK LANDMANN, SCIENCE SOURCE
If Chengzu Long hadn’t been quite so unlucky, he might never have attempted to study and treat Duchenne muscular dystrophy. As a PhD student in Eric Olson’s lab at the University of Texas Southwestern Medical Center, Long had spent years knocking out genes in mice to try to identify their role in muscle development and disease, only to find that each of the resulting knockouts had no discernible differences from wildtype individuals.
In the fall of 2013, with only about a year left until his planned graduation, Long decided to take a different approach: rather than generate yet another knockout mouse that might again lack a phenotype, he would use the new CRISPR-Cas9 gene-editing technique to ...
