FIG. 5.

In vivo recombination between circular DNAs bearing two different regions of luciferase homology. Vaccinia virus-infected cells were cotransfected with the indicated plasmids and recombinant frequencies were calculated as described in Materials and Methods. Plasmids pRP406-S800 and pRP406-S1600 differ in that the stuffer sequences separating the two N = 20-bp and two N = 333-bp homologies are 787 and 1,621 bp long, respectively. Results obtained from three separate experiments are plotted separately to illustrate the experimental variation.