Competition between interchromosomal and intrachromosomal donors.

(A) Scheme for DSB repair in diploid strains. The DSB could be repaired by gene conversion using an ectopic intrachromosomal LEU2 sequence, an allelic leu2-KpnI sequence, or the homologous sequence outside of the leu2-KpnI. Each outcome is revealed by KpnI-digestion of the indicated PCR fragments, yielding respectively 3, 2 and 1 fragments, as illustrated in (C). (B) Usage of ectopic and allelic donors assessed from 31 colonies of individual recombinants in YWW210 (58% intrachromosomal donor usage assessed in pooled cells from S5 Fig and 85% viability in haploid strain from Fig 1). (C) Three types of possible outcomes for individual repair events revealed by KpnI-digestion: (1) repair from intrachromosomal LEU2; (2) allelic repair without URA3 co-conversion; (3) allelic repair with URA3 co-conversion.