Question

Which dye is most commonly used for DNA visualization in agarose gel?

• A. Ethidium bromide
• B. Crystal violet
• C. Coomassie blue
• D. Safranin

Hint:

Always associate Ethidium Bromide (EtBr) with DNA/RNA agarose gels and UV light visualization. Also, remember that it requires careful handling because its intercalating nature makes it a potential mutagen.

Answer 1

The Correct Option is A

The question asks about the dye most commonly used for DNA visualization in agarose gel. Let's discuss the roles and uses of each option provided.

1. Ethidium Bromide: It is a fluorescent dye that intercalates between DNA bases. When exposed to ultraviolet light, ethidium bromide fluoresces, making it easy to visualize DNA bands in agarose gels. This dye is most widely used due to its strong affinity for DNA and ability to produce bright fluorescence when bound to DNA.
2. Crystal Violet: Primarily used for staining cell walls and in general microscopy. It is not ideal for visualizing DNA in agarose gels.
3. Coomassie Blue: This dye is commonly used for staining proteins in polyacrylamide gels after electrophoresis. It is not used for DNA staining as it binds to proteins, not nucleic acids.
4. Safranin: Typically used as a counterstain in various histological techniques. It is not used for DNA visualization in agarose gels.

Among the options provided, Ethidium Bromide is the correct answer. It is the most commonly used dye because of its high fluorescence capability when bound to DNA, facilitating efficient visualization under UV light.

Conclusion: The dye most commonly used for DNA visualization in agarose gels is Ethidium Bromide, making it the correct choice for the given question.