Science: Making a Safer Microbe

Laboratories can be designed to prevent the escape of potentially dangerous organisms. But there is always the chance that something or someone will fail—and that a few virulent bugs will slip through the safeguards to multiply in the outside world. Faced with this problem at the Asilomar conference. Geneticist Roy Curtiss III proposed an ingenious solution: Why not convert the standard genetic research organism, a strain of the E. coli bacterium, into a seriously weakened mutant variety that would quickly self-destruct if it escaped the laboratory? Curtiss volunteered to engineer the new bug,...