Figure 1.

Experiment Design. (A) Each pair of RILs was crossed to produce the F1 hybrid. The hybrids were raised to adulthood, brother-sister mated, and placed into condo wells (three males and three females per well). Each condo contained four RIL crosses exposed to MTX simultaneously. After a 3-d exposure, each condo was recovered for 1 d, and the flies were allowed to lay eggs for 2 d after the recovery stage, after which the adult flies were cleared out of the condo. The eggs developed into adults for 14 d after the condos were cleared, frozen at −20°, and transferred onto adhesive sheets for counting. (B) The entire assay was split into eight blocks, with start dates on consecutive weeks. Each block took 8 wk to complete. F1 hybrids from populations A1×B2 were assayed over the first 3 wk, and any crosses that failed to complete the entire cycle were repeated in weeks 6 and 7. F1 hybrids from populations A2×B1 were assayed in weeks 4 and 5, and the crosses that failed in those two weeks were completed in week 8. (C) Density plot of the mean number of offspring produced by the three replicate females from each RIL. Different colors correspond to different weeks (blocks) of the experiment.