FIG. 1.

(A) Schematic representation of our experimental system. Open rectangles represent the ura3 alleles on chromosomes II and V. A stippled box represents the HOcs; a grey box depicts the inactive HOcs-inc flanked by the BamHI (designated B) and EcoRI (designated R) restriction sites. Transfer of the cells to galactose-containing medium results in a DSB that is repaired by gene conversion. (B) FACS analysis of strains MK203 and MK203rad24. Cells were synchronized at G₁ with α-factor and released into medium containing galactose at 0 h. (C) Exponentially growing MK203 and MK203rad24 cells were artificially arrested at G₂/M with nocodazole, transferred to galactose with nocodazole, and subjected to FACS analysis to confirm complete G₂/M arrest. (D) Aliquots from the same experiment were also plated on glucose at different times after HO induction. Survival was determined as relative number of CFU.