Specific locus method results

A number of techniques have been devised for mutation studies in the mouse, but undoubtedly the most productive has been the specific-locus method, which so far has found its greatest use for the assessment of the genetical hazards of ionizing radiations to man. The method has the potential for fulfilling the same role with respect to environmental and chemical mutagens, and, as the first results already demonstrate, it is likely to provide information which will elucidate the nature of the mutation process in the mammalian germ cell and indicate some of the variables which affect it. 

TABLE 1. Results of Experiments to Detect Chemically Induced Recessive Visible Mutations in Male Mouse Germ Cells by the Specific-Locus Method ... 

TABLE 10. Results of Mutagenic Activity Tests of Chemical Compounds Using the Specific Locus Method in... 

Selby, P.B. and Olson, W.H. (1981). Methods and criteria for deciding whether specific-locus mutation-rate data in mice indicates a positive, negative or inconclusive result. Mutation Res. 83 403-418. 

Specific locus mutations in the ad-3 region result in the accumulation of a purple pigment in the mycelium as well as a requirement for adenine. Mutants are recovered on the basis of pigment accumulation. Our experience has shown that this method of selection enables us to recover not only mutants with complete blocks and partial blocks, but also mutants that are so leaky that we cannot even demonstrate an adenine requirement (de Serres, 1964). In this respect, the ad-3 system is ideal for the detection of the mutagenic activity of chemicals, because we believe that all types of mutagenic activity resulting in the structural alteration of DNA will be detected. 

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