A gain-of-function screen to identify reduced-lifespan genes. (A) Crosses for the primary screen: GS lines were crossed with hs-GAL4, and their F1 progeny were raised, at 18°. Typically, 10 to 20 F1 adult males carrying each GS vector and hs-GAL4 were collected for 5 days after eclosion, reared for another 2 days at 18°, and then heat-shocked at 37° for 20 min. The flies were reared for another 5 days at 25°, and then dead flies were counted. Lethality was calculated as the percentage of total heat-shocked flies that were dead flies. (B) A dot plot showing the lethality (determined by the percentage of survivors 5 days after heat shock) of individual lines; the shaded area in the graph corresponds to 80-100% lethality. GS lines with lethality greater than 80% (227 lines, indicated as 1st positive lines) were used for a secondary screen.