Fig. 5. Atro and Ft act separately in some developmental processes and together in others. (A,A',B) Photoreceptor specification defects in Atro³⁵ mutant clones in the eye imaginal disc. The endogenous equator is marked by the yellow line. Bar staining (A) in red. Yellow arrows (A') designate clusters in which only one cells stains for Bar, indicating loss of R1 or R6 cell fate. Staining for the Prospero (Pros; red in B) a nuclear protein (a marker for R7 and the cone cells) reveals that in several clusters more than one cell has adopted the R7 fate (white arrows). Although the cone cells are mostly located above the plane of this section some of their nuclei (identified by their elongated shape) are present in this picture. (C,C') Atro³⁵ mutant clone marked by the absence of GFP (green). Note the round shape of the clone in front of the morphogenetic furrow (white arrows in C and C') compared with the irregular shape of a clone behind the furrow (small arrowhead in C') and of the twinspots, recognizable because of the brighter green staining due to the double amount of GFP (yellow arrows in C') Elav(red). (D,D') ft^GRV mutant clone marked by the absence of GFP (green), Elav (red). Note the round shape of all the clones both in front of and behind the morphogenetic furrow (white arrows) compared to the irregular shape of the twinspots (yellow arrow). (E-G) Pictures of wt wings (E) or wings carrying ft^GRV (F) or Atro³⁵ (G) mitotic clones. ft and Atro clones (broken yellow lines) generate blisters in which the dorsal and ventral sheet of the wing are separated. (H-J). Dorsal thoraces of a wild-type fly (H) or flies with ft^GRV (I) or Atro³⁵ (J) clones (broken yellow lines). Note the cleft in the thorax, indicating incomplete fusion of the left and right imaginal discs.