Figure 5.—

Alternative ways to generate distal exchange points on CO products. Two alternative ways are considered for the formation of COs with a distal exchange point without long heteroduplexes. One implies the formation of a long asymmetric heteroduplex and the other the migration of a double Holliday junction. In the first alternative, products differ depending on the directionality of resolution. Only resolution 1 gives rise to a molecule with a distal exchange and without a long heteroduplex. In the second alternative, migration of a double Holliday junction and resolution can lead to a CO with a distal exchange point and with small stretches of heteroduplex DNA.