Figure 7.

New replication fork model of λ recombination. As in Fig. 6, the annealing of the ssDNA generated by λ Exo anneals to an ssDNA region on the lagging strand template. In this model, however, the invaded replisome is not affected. Instead, the invasion of the incoming duplex initiates a new fork that travels in the opposite direction, with the annealed strand becoming the template for the new fork’s lagging strand. The incoming duplex is then connected to one arm of the fork (i.e., the recombination event). As before, red trapezoid, λ Exo; blue circles, λ Beta. Yellow oval represents the replisome.