TA100, TA1538, and TA1535 are strains of Salmonella bearing different histidine auxotrophic mutations. The TA100 strain is highly sensitive to reversion through base-pair substitution. The TA1535 and TA1538 strains are sensitive to reversion through frameshift mutation. The test results show that aflatoxin B₁ is a potent mutation that causes base-pair substitutions but not frameshifts.

[Data from J. McCann and B. N. Ames, in W. G. Flamm and M. A. Mehlman, eds. Advances in Modern Technology, vol. 5. Copyright by Hemisphere Publishing Corporation, Washington, D.C.]