A Genetic and Cytological Study of Some X-Ray Induced Mutations and Reverse Mutations in Drosophila melanogaster

The literature pertaining to the problem of mutations, with special reference to reverse mutations and position effect, is reviewed. Data are presented from genetic and cytological studies of several reversions at the Dichaete and Glued loci, of forty-six cases of position effect at the white locus, thirty-six mutations at the light locus and twenty-five mutations at the straw locus. Three of the mutations at the light locus and one of the mutations at the straw locus are shown to be position effects. One case of position effect at the Bar locus and two new mutants, Antennapedia and Scarred, are described. These reversions and mutations were induced by irradiation with X-rays. The effects of adding and subtracting Y-chromosomes, and of temperature upon the light-mutant character of mutants resulting from a position effect at the light locus are demonstrated.