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, two distinct processes play a role. The recombinational interaction between homologous DNA molecules results in the presence of heteroduplex DNA 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 such mismatches can contribute to the separation of closely linked markers. The processes responsible for such repair also play roles in mutation avoidance. The specificities, functions and contribution to the formation of recombinants for closely linked markers of the processes in Escherichia coli are described.