Bacteria have proven to be good models for determining the mutagenic potential of compounds. Bruce Ames, a biochemist, developed an assay to identify potential mutagens. The Ames test works ‘backwards’ from what one might expect. The test starts with mutant bacteria and looks for chemicals that can change them back into normal (wild type) bacteria.

In the Ames test, a potential mutagen is placed on a paper disc in the center of a petri dish on which only bacterial cells that mutate are able to grow. The mutagenic potential of the compound in question is determined by the amount of bacterial growth seen. Information obtained in this way was shown to be comparable to results from tests in rodents.

Researchers have also manipulated mouse cells to make them potential targets for carcinogens and have transferred genes from cancerous cells into healthy mice,–all of which have led to the conclusion that mutations in key genes can lead to the changes that result in cancer. (1)