In [[molecular biology]], '''restriction fragment length polymorphism''' ('''RFLRFLP''') is a technique that exploits variations in [[homology (biology)|homologous]] [[DNA]] sequences, known as [[polymorphism (biology)|polymorphisms]], in order to distinguish individuals, populations, or species or to pinpoint the locations of [[gene]]s within a sequence.The term may refer to a polymorphism itself, as detected through the differing locations of [[restriction site|restriction enzyme sites]], or to a related laboratory technique by which such differences can be illustrated. In '''RFLP analysis''', a DNA sample is digested into fragments by one or more [[restriction enzyme]]s, and the resulting ''restriction fragments'' are then separated by [[gel electrophoresis]] according to their size.
Although now largely obsolete due to the emergence of inexpensive [[DNA sequencing]] technologies, RFLP analysis was the first [[DNA profiling]] technique inexpensive enough to see widespread application. RFLP analysis was an important early tool in [[genome mapping]], localization of genes for [[genetic disorder]]s, determination of [[Genetic testing|risk]] for disease, and [[DNA paternity testing|paternity testing]].
