Bruce Nathan AmesBorn 16 Dec 1929. American biochemist and molecular biologist who developed the Ames test that is an indicator of the carcinogenicity (cancer-causing potential) of chemicals. It measures the rate of mutation in bacteria after the introduction of a test substance. His research led to a greater appreciation of the role of genetic mutation in cancer and facilitated the testing of suspected cancer-causing chemicals. He also developed a data base of chemicals that cause cancer in animals, listing their degree of virulence. In 1997, Ames was one of team of UC Berkeley scientists who discovered the link between low levels of folic acid, an essential nutrient, and breaks that occur in chromosomes and DNA. These breaks could lead to cancer and other diseases.