Figure 1.

(A) The pA–pB crossing design. For each cross, a pA male was crossed to a pB female producing genetically identical trans-heterozygote F1 individuals. (B) The condo layout. Each cross seeded 12 cells, 3 per drug. There were a total of four crosses per condo. (C) The entire assay was split into five blocks, with start dates on consecutive weeks. Each block took 8 weeks to complete. F1 hybrids from populations A1 × B2 were assayed over the first 3 weeks, and F1 hybrids from populations A2 × B1 were assayed in weeks 4 and 5.