Editing Mutagenesis (section)

=== Crosslinking ===
{{Main|Crosslinking of DNA}}

Covalent bonds between the bases of nucleotides in DNA, be they in the same strand or opposing strands, is referred to as crosslinking of DNA; crosslinking of DNA may affect both the replication and the transcription of DNA, and it may be caused by exposure to a variety of agents. Some naturally occurring chemicals may also promote crosslinking, such as [[psoralens]] after activation by UV radiation, and nitrous acid. Interstrand cross-linking (between two strands) causes more damage, as it blocks replication and transcription and can cause chromosomal breakages and rearrangements. Some crosslinkers such as [[cyclophosphamide]], [[mitomycin C]] and [[cisplatin]] are used as anticancer [[Chemotherapy|chemotherapeutic]] because of their high degree of toxicity to proliferating cells.