Homologous Recombination by the RecBCD and RecF Pathways RECOMBINATIONAL REPAIR OF DNA DAMAGE

Homologous, or general, recombination is a cru-cial biological process that involves the paring and transfer of strands between DNA molecules that share a region of significant sequence homology. After its discovery in 1946 by Lederberg and Tatum (48), ho-mologous recombination in bacteria was associated with the sexual process of conjugation and was viewed as an evolutionary mechanism both for shuffling the genome and for spreading favorable alleles. However, more recently, a more immediate function of homol-ogous recombination has been recognized: namely, it is a mechanism for the maintenance of chromosomal integrity that acts to repair DNA lesions, both double-strand DNA breaks and single-strand DNA gaps, gen-erated during the course of DNA replication. Th