SUICIDAL GENETIC ELEMENTS AND THEIR USE IN BIOLOGICAL CONTAINMENT OF BACTERIA

The potential risks of unintentional releases of genetically modified organisms, and the lack of predictable behavior of these in the enviro nment, are the subject of considerable concern. This concern is accent uated in connection with the next phase of gene technology comprising deliberate releases. The possibilities of reducing such potential risk s and increasing the predictability of the organisms are discussed for genetically engineered bacteria. Different approaches towards designi ng disabled strains without seriously reducing their beneficial effect s are presented. Principally two types of strain design are discussed: actively contained bacteria based on the introduction of controlled s uicide systems, and passively contained strains based on genetic inter ference with their survival under environmental-stress conditions.