Somatic gene mutagenicity and killing effects of N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) in Drosophila melanogaster were investigated by comparing the sensitivity of the DNA repair-proficient and the repair-deficient assaying systems. Somatic chrom...
Somatic gene mutagenicity and killing effects of N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) in Drosophila melanogaster were investigated by comparing the sensitivity of the DNA repair-proficient and the repair-deficient assaying systems. Somatic chromosome mutation was also investigated by the wing spot test system. The killing effects of MNNG on the repair-deficient uz : mus 201/mus 201 strain were 25 to 30 times great than that on the repair-proficient uz system. All of the repair-proficient and deficient systems showed a strong positive response to mutagenicity of MNNG, and the uz : mus 201/mus 201 strain was more sensitive than the uz strain to somatic gene mutations by MNNG. In the mwh/flr strain, which is a wing spot test system, mutations increases with the dose of MNNG. The present results about the frequency of large single spots and twin spots suggest that MNNG induce more gene mutation and chromosomal recombination than nondisjunction and deletion. The large single spots induced by MNNG had a modal frequency of which 5-16 cells which was smaller 2-3 cell cycles than 65-128 cells obtained by X-irradiation and 33-256 cells induced by neutrons at the same larval stage.