Figure 3.

Model of Sgs1 in S. cerevisiae within meiotic recombination. A: After formation of a DSB, 5′ ends are resected to reveal 3′ tails. B: 3′ tails can inappropriately invade multiple homologs or sister chromatids (not pictured) to create aberrant joint molecules. These joint molecules are unwound by Sgs1 to regenerate the 3′ resected ends. C: The 3′ tail can invade the homologous chromosome to create a D-loop. D: A D-loop can be processed by the Class I pathway, to be subsequently stabilized by the MutSɣ complex and resolved by MutLɣ complex to generate a patterned crossover. E: D-loops that have undergone synthesis can be unwound by Sgs1, creating noncrossovers via SDSA. Sgs1 can unwind the D-loop if synthesis did not occur, or if there is too little synthesis for complementarity, Sgs1unwinds to regenerate the resected intermediate with some synthesis. F: D-loops can be processed by the Class II pathway, where they are eventually cleaved into equal ratios of crossovers to noncrossovers.