Fig. 8. Genetic rescue of lace^k05305 by Sply⁰⁵⁰⁹¹. The lace^k05305 allele is almost completely lethal and the few homozygotes that do survive to adulthood have a lifespan of less than 1 week and manifest pronounced morphological defects (A,C). Wings are notched and often fail to inflate, bristles are missing (arrows), and the eyes are often rough with irregular ommatidia. The addition of the Sply⁰⁵⁰⁹¹ allele (B,D) greatly improves viability, and external morphology is indistinguishable from wild-type flies.