Note on Drosophila as a mutagenicity test system.

By virtue of its considerable genetic versatility, Drosophilk melanogaster may be used to detect, in the entire array of germ cell stages, a wide spectrum of chemically induced genetic alterations, including those with severe or obvious effects, such as dominant lethals, chromosome loss, complete and mosaic translocations, recessive lethals, and "visibles", and nondisjunction, as well as those causing only mildly detrimental effects but which in aggregate may be as harmful as mutations with severe effects (1-3). Since the former are far more readily detected than the latter, and include the major types of genetic damage responsible for abortions, diseases, abnormalities, and malfunctionings in humans, they are as a group, of obvious primary concern in any mutagenicity testing program. The two most widely used procedures used in Drosophila screening for genetic alterations in postmeiotic, meiotic, and premeiotic cells (and in existence now for more than four decades) are the sex-linked recessive lethal test and the translocation test, often combined, in practice, in the same experiment [see Abrahamson and Lewis (4) for details of procedure]. The sex-linked recessive lethal test detecting recessive mutations (associated or not with chromosome aberrations) arising in the X chromosome of male germ line cells, is probably the most utilitarian in the battery of procedures available