DNA topology is the focus of a subdiscipline within molecular biology and as a term refers to both the knot-like arrangements that segments of DNA may assume and to the mathematics that pertains to them. The topology of DNA topoisomers is important to replication, transcription and recombination, including the recombination events important to the life cycles of many viruses. Topoisomerases are enzymes that change the topology of DNA.
See also: supercoil, knot theory