Fig. 1.

Model for conservative or semiconservative DNA synthesis during BIR. If the Rad51-catalyzed D-loop migrates to the chromosome end (tel) and lagging-strand synthesis initiates on the displaced nascent strand, both newly synthesized strands (shown in blue) will segregate with the recipient (R) chromosome. Cleavage of the strand invasion intermediate by a structure-selective nuclease and establishment of a replication fork is predicted to result in semiconservative synthesis detected by segregation of the newly synthesized strands to donor (D) and recipient chromosomes.