A form of DNA repair that fills large gaps in a new DNA strand resulting from failure of replication. It prevents gross chromosomal abnormalities and enables timely replication of DNA in the S phase of the cell cycle. In trans-lesion synthesis, special polymerase enzymes synthesize a new DNA strand across the lesion that blocked the replicative polymerase. This is relatively prone to error but does restore genome stability and allow subsequent precision repair by, e.g., mismatch repair. Template switching is an alternative mechanism that ‘borrows’ the information from a newly synthesized daughter strand as a template to synthesize a new strand that bypasses the lesion responsible for the gap. This is an error-free mechanism of postreplicative repair.