Restriction fragment length polymorphism (RFLP)

Abstract

A restriction fragment length polymorphism (RFLP) is defined by an enzyme, a restriction endonuclease, that cuts the doublestranded DNA at a particular sequence of bases, a probe, a labeled, complementary segment of DNA that will anneal to a portion of the digested sample, and a set of variable fragment length bands that appear on a Southern blot. An elementary discussion of restriction enzymes, their nomenclature, recognition sequences, and activities is presented. This is followed by a basic description of the RFLP and its components, electrophoresis, the Southern blot, and hybridization. Simple DNA polymorphisms are illustrated in light of the nomenclature for RFLPs in human gene segments of known function and those that are anonymous. It is shown that the majority of RFLP loci have two alleles, while a subset, the minisatellite and some variable number of tandem repeat (VNTR) loci, exhibit hypervariability. Applications of RFLP technology to parentage testing, human gene mapping, prenatal diagnosis, and evolutionary studies complete the essay. Copyright © 1989 Wiley‐Liss, Inc., A Wiley Company