Ethyl methanesulfonate: an effective mutagen in Chlamydomonas reinhardi

Summary The effectiveness of ethyl methanesulfonate (EMS) as a mutagen inChlamydomonas reinhardi has been demonstrated in two different systems: reversion to prototrophy of an argine-requiring strain and forward mutation to auxotrophy of the wild-type strain. In these experiments, the toxic effect of EMS was very low. With certain batches of EMS, an unusually high toxicity was observed. In this case, the lethal effects seem to be attributable to the presence of minor impurities in EMS.Chargé de Recherches au Fonds National de la Recherche Scientifique.