FIG. 1.

DNA repair pathways in mammals. The five major DNA repair pathways are direct reversal, DNA BER, NER, DNA MMR, and DNA DSBR. The Venn diagram illustrates relations of repair systems to one another. A few DNA repair enzymes function in multiple pathways, as denoted by the overlaps in the diagram. DNA damage can be bypassed during DNA replication by bypassing DNA polymerases. BER, base excision repair; NER, nucleotide excision repair; MMR, mismatch repair; DSBR, double-strand break repair.