Practice question

Amplified fragment length polymorphism involves sequential steps of complete genomic DNA digestion with rare and frequent cutting enzymes, ligation of double-stranded adapters to fragment ends, pre-selective amplification with primers having one selective nucleotide, followed by selective amplification with primers containing two or three additional selective nucleotides labeled for detection. This two-step PCR reduces complexity and increases specificity, generating fifty to one hundred scorable bands per reaction. Random primer methods or single-step protocols lack this nested selectivity and reproducibility characteristic of AFLP fingerprinting.