Figure 3.

Forward genetic mutagenesis scheme using EMS to induce DNA mutations. (A) A standard hemizygous recessive screen for the X chromosome. FM7i is a “green balancer” expressing GFP in a pattern distinct from the actin∷GFP chromosome, allowing genotyping of progeny by epifluorescent visualization. (B) A standard recessive F₂ screen for the second chromosome. Progeny can be genotyped by the presence of one or two insertions of the actin∷GFP transgene detected by epifluorescent visualization. Heterozygous or homozygous mutant second chromosomes correspond to one or two actin∷GFP insertions, respectively.