Random amplification of polymorphic DNA

Random amplified polymorphic DNA (RAPD), pronounced "rapid", is a DNA profiling technique that generates simple genomic fingerprints without requiring sequence information. Developed in the very early 1990s by Antoni Rafalski and colleagues at E.I. du Pont de Nemours (Wilmington, Delaware, USA), the technique uses short arbitrary primers, typically 10–12 nucleotides (nt) in length, and a polymerase chain reaction (PCR), to amplify anonymous regions in genomic DNA useful for genetic typing, strain discrimination, genome mapping, molecular ecology and population analysis. Primers anneal at numerous partially complementary sites, and those that occur in opposite orientation and within amplifiable distance (generally < 3–5 kb) are amplified and visualized by agarose gel electrophoresis and ethidium bromide staining. RAPD belongs to a family of arbitrarily amplified DNA profiling methods that include DNA amplification fingerprinting (DAF) and arbitrarily primed PCR (AP-PCR). These techniques use higher primer-to-template DNA ratios and shorter and longer primers, respectively, and produce more complex fingerprinting patterns.