Fig. 4. Loss of Ser affects ventral growth. (A) Ser– clones, marked by the absence of lacZ (red), did not affect eye size or photoreceptor cluster formation in either domain. (B) An eye disc that contains SerDN flp-out clones. Overexpression of SerDN decreased ventral cell viabilities such that only small ventral clones were observed. By contrast, there were more dorsal clones and they were considerably larger. (C) Overexpression of SerDN by the ey-Gal4 driver abolished eye development. (D) SerDN flp-out clones caused a preferential loss of the ventral domain, similar to L.