SOME FEATURES OF BASE-PAIR MISMATCH REPAIR AND ITS ROLE IN THE FORMATION OF GENETIC RECOMBINANTS

For the formation of recombinants involving closely linked markers, tw o distinct processes play a role. The recombinational interaction betw een homologous DNA molecules results in the presence of heteroduplex D NA joining the parental components of the recombinant. The presence of markers distinguishing the parents in the region of heteroduplex DNA can result in base pair mismatches. The post recombination repair of s uch mismatches can contribute to the separation of closely linked mark ers. The processes responsible for such repair also play roles in muta tion avoidance. The specificities, functions and contribution to the f ormation of recombinants for closely linked markers of the processes i n Escherichia coli are described.