Figure 4.

Adaptive gain-of-mutation is linked to nuclear gene. Zygotes from mating of adapted cybrids with S. paradoxus CBS 7400 mtDNA and W303 1A/YEp352 ρ⁰ strain were sporulated and tetrads dissected. Colonies from individual spores were spotted on different media. (3–6) Four individual tetrads; Controls: (1) MCC109 ρ⁰; (2) cybrid with S. paradoxus CBS 7400 mtDNA; (7) W303 1A ρ⁺; (8) W303 1A ρ⁰. Plates (A) YPD 30°C; (B) YPD 37°C; (C) YPGE 37°C; (D) YPGE 30°C. Cultivated 3 days at 28°C.