(1975) Detection of specific sequences among DNA fragments separated by gel electrophoresis J. (1984) DNA markers for nervous system diseases. A., Hobbs, W., Gibbons, K., Raschtchian, R., Gilliam, T. (1986) A repetitive DNA family ( Sau3A family) in human chromosomes extrachromosomal DNA and DNA polymorphism. (1983) Closely related species of Drosophila can contain different libraries of middle repetitive DNA sequences Chromosoma 88, 104–108. ![]() (1983) Molecular basis of length polymorphism in the human ζ-globin gene complex. (1982) The highly polymorphic region near the human insulin gene is composed of simple tandemly repeating sequences. (1980) A highly polymorphic locus in human DNA. (1978) Polymorphism of DNA sequence adjacent to human β-globin structural gene: relationship to sickle mutation. (1992) Restriction enzymes and their isoschizomers. In the nuclear genome, polymorphisms also reflect different locations of the same sequence (repetitive or transposable DNA), owing to different flanking DNA (7,8). Changes in restriction fragment patterns result not only from point mutations but also from deletions, insertions, or duplications that alter the length of fragments (4–6). Fragments generated by other enzymes would reflect positions of different restriction sites along the same region of DNA and would reveal changes in the additional sets of nucleotides. Such differences, resulting from genetic divergence, would be manifested in the length of fragments generated by the enzymes and separated by electrophoresis. Likewise, nucleotide changes may create new sites. If a sequence recognized by a restriction enzyme is altered by a substitution of any of the nucleotides, it would not be cleaved. In fragmenting DNA, restriction enzymes can be used as a reflection of the nucleotide sequences that they recognize, allowing genetic distinction based on a small percentage of the genome, without having to sequence the DNA (3). DNA fragments of discrete lengths are generated, which can be separated by electrophoresis through a gel matrix. These enzymes cut DNA at specific short sequences, commonly consisting of four to six nucleotides (2). RFLP produces a series of bands when a Southern blot is performed with a particular combination of restriction enzyme and probe sequence.įor example, let's follow a particular RFLP that is defined by the restriction enzyme EcoR I and the target sequence of 20 bases GCATGCATGCATGCATGCAT.With the discovery of bacterial “restriction endonucleases” (1), it became possible to fractionate the long DNA molecule, so that specific regions could be analyzed. When a probe base pairs to its target, the investigator can detect this binding and know where the target sequence is since the probe is detectable. A probe is a sequence of single-stranded DNA that has been tagged with radioactivity or an enzyme so that the probe can be detected. A target sequence is any segment of DNA that bind to a probe by forming complementary base pairs. An RFLP is a sequence of DNA that has a restriction site on each end with a " target" sequence in between. Since DNA is replicated with each generation, any given sequence can be passed on to the next generation. On this web page, you can see how RFLPs are produced and then three examples of applying RFLP analysis: paternity, disease status, and genetic mapping.Įach organism inherits its DNA from its parents. RFLPs can be used to measure recombination rates which can lead to a genetic map with the distance between RFLP loci measured in centiMorgans. RFLPs can be used determine the disease status of an individual. ![]() RFLPs can be used in paternity cases or criminal cases to determine the source of a DNA sample. RFLPs can be used in many different settings to accomplish different objectives. RFLP (often pronounced "rif lip", as if it were a word) is a method used by molecular biologists to follow a particular sequence of DNA as it is passed on to other cells. RFLP Method - Restriction Fragment Length Polymorphism
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