A mutagen is any treatment or chemical substance that can induce heritable changes in genetic material and thereby increase mutation rates. For many decades scientists have been making use of such mutagens with aims as diverse as, on the one hand, increasing yields in strains used for commercial antibiotic production, to, on the other hand, the search for the variants that assist molecular biologists in understanding fundamental cellular processes. For some time, however, it has been apparent that as well as being useful tools, mutagens can be dangerous human health hazards. In particular, a high proportion of mutagens have been shown to have carcinogenic activity. Conversely, 85% of known human carcinogens were found to be mutagenic when tested on bacteria.
