Drug screen using DX1 Drosophila. (A) Diagram depicting using Drosophila to screen for heterochromatin-promoting small molecule compounds. Three w1118/Y; DX1/CyO males and three virgin w1118 were crossed at room temperature and allowed to lay eggs for two days. Parent flies were then removed and 60 µl of 33% DMSO in water with 10 µM compound was pipetted onto food two days and four days after crosses were first set up. The eye phenotype of w1118/Y; DX1/+ F1 male progeny were then scored. (B) Eye phenotype scoring scale. Representative pictures representing the score assigned to flies based on eye color variegation as the following. 1: mostly white with light spots of red/orange scattered in <10% total surface area. 2: Patches of red spots in >10% but <30% of the surface area. 3: Red spots in 50% of surface area. 4: Red spots range from 50% to 70% of eye surface. 5: Red spots occupy >70% of the eye surface.