What is the principle of restriction fragment length polymorphism (RELP) technique?

Restriction fragment length polymorphism (RFLP) is an enzymatic procedure used to separate and identify target DNA fragments. It is based on the principle that if two organisms have differences in the distances between cleavage sites for a specific restriction endonuclease, the lengths of the DNA fragments generated will vary when the DNA is digested with that restriction enzyme. These differences in fragment length patterns can be used to distinguish between species and even between strains.