Difference between linear and circular restriction mapping
Answers
Digestion of a linear DNA molecule with a restriction endonuclease (RE) that makes a single cut produces two fragments. In contrast, digestion of a circular DNA molecule with any RE that makes a single cut produces a single linearized fragment, all of which are necessarily of identical size. In the example, A & B each produce a linearized circular molecule, length 17kb [far left]. Inspection of the AB double digest data shows that the A & B sites are 5kb apart. The unique map of A & B is thus easily drawn [left, middle].
A restriction map is a map of known restriction sites within a sequence of DNA. Restriction mapping requires the use of restriction enzymes. In molecular biology, restriction maps are used as a reference to engineer plasmids or other relatively short pieces of DNA, and sometimes for longer genomic DNA. There are other ways of mapping features on DNA for longer length DNA molecules, such as mapping by transduction.[