The procedure used to separate and analyze DNA fragments, or RFLPs, is called

• A. Polymerase Chain Reaction
• B. Sequencing
• C. Cloning
• D. Gel Electrophoresis

Answer: (D)

Gel electrophoresis separates DNA fragments by size. In this method, DNA is loaded into a gel and an electric current is applied, pulling the negatively charged DNA toward the positive electrode. The gel matrix acts like a sieve: smaller fragments move through it more quickly than larger ones, so the fragments form distinct bands at different positions. When analyzing RFLPs, DNA is first cut with restriction enzymes to create fragments of varying lengths. Running these fragments on a gel yields a banding pattern that reflects the length differences between individuals, enabling comparison and interpretation of polymorphisms. The other techniques have different purposes—PCR amplifies DNA, sequencing reads the exact nucleotide order, and cloning creates copies or constructs—whereas gel electrophoresis directly separates and analyzes fragment sizes.