Figure 2.

Summary of the screen. (A) Crossing scheme for identifying dominant modifiers of the MS1096>Dp110^KD small-wing phenotype. EMS-mutagenized FM7/Y males were mated with homozygous MS1096>Dp110^KD virgin females. F₁ flies with mutations that either enhanced or suppressed the small-wing phenotype were individually backcrossed to the MS1096>Dp110^KD strain to check whether the modifying effect was transmitted to the next generation. The FM7 chromosome itself does not modify the small-wing phenotype (data not shown). Modifiers that bred true were retained, mapped to chromosomes, and balanced. “E/S” represents possible enhancer or suppressor point mutations, respectively, induced by the EMS mutagen. “Y” indicates the Y chromosome and thus identifies the male flies in the crossing scheme. (B) Flow diagram indicating the number and type of modifiers retained at each stage of the initial chromosomal mapping and complementation analyses. Numbers in parentheses in the bottom boxes indicate the number of mutant alleles in each complementation group. Note that the E-3c group was subsequently found to comprise two lethal complementation groups of two alleles and three single hits—see text for details.