Amplified Fragment Length Polymorphism (AFLP) technology is a technique for fingerprinting genomic DNA. DNA fingerprinting is used to visualize DNA polymorphisms between samples. These fingerprints may be used as a tool for determining the identity of a specifc DNA sample, or to assess the relatedness between samples.
AFLP technology is based on classical, hybridization-based fingerprinting and PCR-based fingerprinting. (See AFLP Procedure Diagram) It is based on the selective amplification of a subset of genomic resriction fragments using PCR. DNA is digested with restriction endonucleases and double-stranded template DNA for amplification. Thus, the sequence of the adapters and the adjacent restriction site serve as primer binding sites for subsequent amplification of the restriction fragments by PCR. Selective nucleotides extending into the restriction fragments are added to the 3' ends of the PCR primers such that only a subset of the restriction fragments are recognized. Only restriction fragments in which the nucleotides flanking the restriction site match the selective nucleotides will be amplified. The subset of amplified fragments are then analyzed by denaturing polyacrylamide gel electrophoresis to generate the fingerprint.
When the DNA fingerprints of related samples are compared, common bands, as well as differing bands will be observed. These differences, referred to as DNA polymorphisms, are observed in an otherwise identical fingerprint. Polymorphisms detected in DNA fingerprints obtained by restriction cleavage can result from alterations in the DNA sequence including mutations abolishing or created by a restriction site, as well as insertions, deletions, or inversions between 2 restriction sites. The DNA polymorphisms identified using AFLP are typically inherited in Mendelian fashion and may, therefore, be used for typing, ID of molecular markers, and mapping of genetic loci.
