Practice question

Restriction fragment length polymorphism originates when nucleotide substitution, insertion or deletion abolishes or creates a specific recognition sequence for a restriction endonuclease. Digestion then yields fragments of altered length detected by gel electrophoresis or Southern blotting after hybridization with labeled probes. This change segregates in Mendelian fashion as allelic variation inherited codominantly. It does not involve repeat expansion, primer binding differences observed in RAPD, or slippage mispairing responsible for microsatellite instability. Thus, point mutations at restriction sites underlie observed band polymorphism pattern.