Fig. 9. Two different Minute mutations affect Atonal expression, whereas Egfr alleles do not. Eye discs stained for Atonal are shown inA-C,E,F,H,I,K,L,N,O,Q,R. Clones are negatively marked by ß-gal (white in D,G,J,M,P, blue in F,I,L,O,R) and are outlined. (A-C) Egfr alleles in trans to wild type; note normal Atonal expression. (D-R) hs:Flp-induced clones induced in trans to Minute chromosomes. (D-O) ß-gal-positive territories are heterozygous for the Egfr allele and for the Minute mutation. Black (ß-gal negative) territories are homozygous for the Egfr allele and are wild type for the Minute mutation. (P-R) ß-gal-positive territories are heterozygous for the Minute mutation. Black (ß-gal negative) territories are genetically (but not phenotypically) wild type. No Minute^– homozygous cells survive. Mutations are indicated on the left. Note, the Atonal pattern is not wild type in either the Egfr homozygous (black in D-O) or the Egfr heterozygous territories (compare the ß-gal-positive regions to the heterozygous examples shown in A-C). Also, the Atonal pattern is not wild type in either the wild-type territories (white arrows in P-R) or the adjacent Minute heterozygous cells (black arrows in P-R). Note that Minute(2)53 and Minute(2)56i have different, but self-consistent dominant effects on Atonal expression. Atonal expression in the Egfr^tsla Minute⁺ clones is indistinguishable from that in the two Egfr null alleles. Scale bar: 10 µm.