What is the purpose of staining the DNA gel with ethidium bromide?

To visualize DNA fragments in exposed UV light

The correct answer is Option (1)- To visualize DNA fragments in exposed UV light

Explanation: Ethidium bromide is a fluorescent dye commonly used to stain DNA in agarose gels. When ethidium bromide intercalates between the base pairs of the DNA, it becomes fluorescent. After gel electrophoresis, the gel is exposed to UV light, and the ethidium bromide-stained DNA bands emit a bright orange fluorescence, allowing researchers to visualize and analyze the separated DNA fragments.

Without staining with ethidium bromide and exposure to UV light, DNA fragments are not visible in visible light, making it impossible to observe and analyze the results of gel electrophoresis. The staining process enhances the sensitivity and resolution of the DNA bands, enabling researchers to identify specific DNA fragments, estimate their sizes, and analyze the results of experiments such as gene cloning, genetic fingerprinting, and DNA sequencing.