DOSE AND EFFECT OF METHYL-2-BENZIMIDAZOLYLCARBAMATE IN THE MAMMALIAN SPOT-TEST, AN INVIVO METHOD FOR THE DETECTION OF GENETIC ALTERATIONS IN SOMATIC-CELLS OF MICE

In the spot test, mouse embryos which are heterozygous for 4 different recessive coat-color genes are treated in utero by injection of a mutagen into the peritoneal cavity of the mother or by other appropriate routes of administration. If this treatment leads in a pigment precursor cell to an alteration of the wild type allele of one of the genes under study or to its loss, a color spot in the adult coat may be seen. Peroral application of 100-300 mg methyl-2-benzimidazolylcarbamate (MBC)/kg to the mother during the 10th day postconception led to an increase in the frequency of color spots in the coats of offspring. The data are consistent with the hypothesis that MBC is a point mutagen.