ASCP Molecular Biology (MB) Technologist Practice Exam

The process used to visualize DNA fragments in Restriction Fragment Length Polymorphism (RFLP) analysis is gel electrophoresis. RFLP involves digesting DNA with restriction enzymes that cut the DNA at specific sequences, resulting in fragments of varying lengths. These fragments are then separated based on size through gel electrophoresis.

In gel electrophoresis, an electric current is applied to a gel matrix containing the DNA fragments. Since DNA is negatively charged due to its phosphate backbone, it migrates toward the positive electrode. Shorter DNA fragments move faster and farther through the gel than longer fragments, allowing for the separation of the fragments based on their length. After electrophoresis is complete, the gel is stained with a DNA-binding dye, which enables visualization of the separated DNA bands under UV light. This visual representation allows researchers to analyze the size of the DNA fragments and determine genetic variations among individuals.

Other techniques mentioned, such as Polymerase Chain Reaction (PCR), Mass Spectrometry, and Fluorescent In Situ Hybridization (FISH), serve different purposes in molecular biology and do not provide the visualization of DNA fragments generated by RFLP directly. PCR is primarily used for amplifying DNA, while Mass Spectrometry is used for analyzing the