ON THE RECOVERY OF SINGLE SPOTS WITH THE FLR PHENOTYPE IN THE WING SPOT-TEST IN DROSOPHILA

Graf et al. (U. Graf, F.E. Wurgler, A.J. Katz, H. Frei, H. Juon, C.B. Hall, P.G. Kale, Somatic mutation and recombination test in Drosophila , Environment Mutagen. 6 (1984) 153-188.) described the overall result s of assays of a series of compounds in the Drosophila wing spot test as indicating that single mwh spots appeared most frequently, followed by less frequent twin spots with both mwh and flr cells and lastly th e 'quite rare' single flr spots. Data are presented below demonstratin g that some compounds behave in a manner consistent with the above des cription, whereas others do not in that the frequency of single flr sp ots is equal to or exceeds that of twin spots and cannot be described as occurring 'rarely'. It is suggested that (large) flr singles be use d as a measure of mutations/deletions directly from treated transheter ozygotes. An argument is presented questioning the use of treated mwh +/+ TM3 individuals as an assay of mutations/deletions at the mwh(+) l ocus. (C) 1997 Elsevier Science B.V.