Final answer:
The Ames test determines a substance's mutagenic potential using a histidine auxotroph strain of Salmonella typhimurium, with comparison to control samples indicating mutagenicity and potential carcinogenicity.
Step-by-step explanation:
The Ames test is utilized to evaluate the mutagenic and potential carcinogenic properties of substances by using a bacterium that cannot synthesize the amino acid histidine. This bacterium, a strain of Salmonella typhimurium, is a histidine auxotroph and is exposed to the chemical in question. In the presence of a potential mutagen, the bacteria that regain the ability to produce histidine are counted and compared to a control to determine the compound's mutagenicity. Often used in conjunction with rat liver extract to simulate metabolism, the Ames test offers a rapid and cost-effective alternative to lengthy animal testing.
Through this process, scientists can infer the likelihood that a given substance will contribute to cancerous mutations. However, positives and negatives can occur, and therefore further testing using animal models may follow a positive Ames test. This procedure reflects the one gene-one enzyme hypothesis, as delineated by Beadle and Tatum, which posits that each gene is responsible for the production of a single enzyme.