Relation between the somatic toxicity of dimethylnitrosamine and a genetically determined variation in the level and induction of cytochrome P450 in Drosophila melanogaster.

The insecticide-resistant Drosophila strain Hikone R differs genetically from sensitive strains by having a higher activity of cytochrome P450 and a lack of inducibility with phenobarbital. Toxicity tests with dimethylnitrosamine (DMN) showed that: (a) the toxic effect of DMN was higher in the insecticide-resistant strain than in sensitive strains in accord with data by Vogel (1980); and (b) induction with phenobarbital increased the toxicity of DMN in the sensitive strains but not in the resistant strain. A dominant gene, responsible for the metabolic pattern of Hikone R and the non-inducibility, was located to 66 cM, near the gene vg in chromosome 2. This gene is most likely identical with that causing insecticide resistance, described by Kikkawa (1961).