Restriction fragment length polymorphism (RFLP) is a type of polymorphism that results from variation in the DNA sequence recognized by restriction enzymes. RFLP, as a molecular marker, is specific to a single clone/restriction enzyme combination. RFLP has been a very popular fingerprinting technique. RFLP Marker By Afnan Said Zuiter · Definition • (often pronounced "rif lip", as if it were a word · Polymorphism • RFLPs have polymorphisms (length. Restriction fragment length polymorphisms (RFLP) have become key elements in systems to diagnose diseases. RFLP is one of the earliest molecular markers developed for genetic mapping.