<P> The Ames test is a widely employed method that uses bacteria to test whether a given chemical can cause mutations in the DNA of the test organism . More formally, it is a biological assay to assess the mutagenic potential of chemical compounds . A positive test indicates that the chemical is mutagenic and therefore may act as a carcinogen, because cancer is often linked to mutation . The test serves as a quick and convenient assay to estimate the carcinogenic potential of a compound because standard carcinogen assays on mice and rats are time - consuming (taking two to three years to complete) and expensive . However, false - positives and false - negatives are known . </P> <P> The procedure was described in a series of papers in the early 1970s by Bruce Ames and his group at the University of California, Berkeley . </P>

The best test of the mutagenic potential of a substance would be