Question

How are separated DNA bands visualized following agarose gel electrophoresis?

Options

• By treating with DNA ligase and observing dark blue precipitate in sunlight

• By adding radioactive phosphorus isotopes and exposing to infrared radiation

• By staining with methylene blue and viewing directly under white visible light

• By staining the gel with ethidium bromide and exposing it to ultraviolet (UV) radiation

Answer 1

Pure DNA cannot be seen under visible light. The gel is stained with ethidium bromide and exposed to ultraviolet (UV) radiation, making the DNA bands visible as bright orange-coloured bands.