Practice question

Synthesis-dependent strand annealing represents a conserved non-crossover pathway predominant in mitotic cells and also during mating-type switching. After invasion and limited repair synthesis extending the invading 3' end using donor as template, the nascent strand dissociates from D-loop, propelled by helicases such as Mph1 or FANCM. It then anneals back to complementary sequences on the second resected end of original break. Gap filling and ligation restores two intact duplexes without reciprocal exchange of flanking arms, suppressing potentially deleterious crossovers, loss of heterozygosity, and chromosome rearrangements.