3.1. Choice of Mutagen
A long held notion, which probably has been influencing the choice of mutagen types (chemical vs. physical), is that chemical mutagens preferentially induce point mutations while physical mutagens induce gross lesions, such as chromosomal breakages and rearrangements. This view has probably been aided by the relative ease for procuring chemical mutagens as well as simpler set-up requirements. Current empirical data do not support this conclusion; rather the more plausible inference from available information is that the frequency and types of mutations are direct results of the dosage and rate of exposure or administration of the mutagen rather than its type. This implies