Skip to content
Login Register

#SDSA pathway

2 public questions tagged with this topic.

Recombination

SDSA pathway mainly results in

Synthesis-dependent strand annealing represents predominant mitotic homologous recombination pathway designed to avoid crossovers. After limited invasion and extension of one 3' end using donor chromatid as template, polymerase delta synthesizes short tract, then disrupted D-loop releases nascent strand through action of Mph1, Srs2, RTEL1, or FANCM helicases, restoring donor duplex unchanged. Dissociated strand anneals to second broken end, allowing fill-in synthesis and ligation without formation of stable double Holliday junction. Genetic markers flanking break remain parental configuration, thereby generating only non-crossover recombinants, critical for genome stability.

Ref: NCBI Bookshelf, Biochemistry, SDSA Pathway Results in Non-Crossover Products

View Details
Recombination

SDSA pathway results in

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.

Ref: Lodish et al., Molecular Cell Biology, 9th ed., Chapter 13: SDSA and Non-crossover Recombination Control

View Details