Direct recombinogenic effect of dimethylnitrosamine (DMN) on zygotes of Chlamydomonas reinhardtii

Summary We developed a test system with mutant strains of Chlamydomonas reinhardtii requiring arginine. Here, the meiotic recombination between two arginine loci served as an indicator of genotoxicity. After crossing, zygotes were treated with the alkylating agent dimethylnitrosamine (DMN) for 30 min. A dose dependent increase of wild type recombinants was found for DMN concentrations ranging from 68 M to 680 M. Like in cells of some higher plants, the agent was active in Chlamydomonas zygotes without any exogenous metabolic activation.