Fig. 1. Wing phenotypes of gbb. (A) A wild-type wing. The five longitudinal veins L1-L5 are indicated, as well as the two crossveins, the anterior crossvein (acv) and posterior crossvein (pcv). The A/P compartment boundary is indicated with a broken line. (B) A gbb1/gbb4 wing illustrating a moderate gbb phenotype. The PCV is absent as well as the distal tips of L4 and L5 (arrows). (C) A gbb3/gbb4 wing showing the most severe phenotype produced by the gbb hypomorphic alleles. The PCV is absent, L5 is truncated almost to the base and L4 is truncated distally (arrow). Note that in both B and C, the overall wing size is reduced compared with the wild-type wing in A.