1) Fragment of DNA of predictable size resulting from digestion (cutting) of a strand of DNA by a given restriction enzyme. DNA sequence alterations (mutations) that destroy or create the sites at which a restriction enzyme cuts DNA change the size (and number) of DNA fragments resulting from digestion by a given restriction enzyme.

2) Variation between individuals in DNA fragment sizes cut by specific restriction enzymes; polymorphic sequences that result in RFLPs are used as markers on both physical maps and genetic linkage maps. RFLPs usually are caused by mutation at a cutting site.

3) Restriction fragment length polymorphism (RFLP) is a type of polymorphism that results from variation in the DNA sequence recognized by restriction enzymes. These are bacterial enzymes used by scientists to cut DNA molecules at known locations. RFLPs (pronounced "rif lips") are used as markers on genetic maps. Typically, gel electrophoresis is used to visualize RFLPs.

4) Variation in the length of a restriction fragment produced by a specific restriction enzyme acting on DNA from different individuals that usually results from a genetic mutation (as an insertion or deletion) and that may be used as a genetic marker -- called also RFLP.