Ethidium bromide is the most commonly used dye for DNA and RNA detection in gels. Ethidium bromide is a DNA intercalator, inserting itself between the base pairs in the double helix. Ethidium bromide has UV absorbance maxima at 300 and 360 nm, and an emission maximum at 590 nm.
Ethidium Bromide (EtBr) is sometimes added to running buffer during the separation of DNA fragments by agarose gel electrophoresis. It is used because upon binding of the molecule to the DNA and illumination with a UV light source, the DNA banding pattern can be visualized.
Although ethidium bromide is routinely used to stain DNA in gels, ethidium bromide has also been used to detect protein–DNA complexes in band shift assays and to observe single DNA molecules during gel electrophoresis.
To add context, ethidium bromide is a carcinogenic intercalating fluorescent dye that binds to DNA and is often used in agarose gel electrophoresis to visualize PCR products, plasmid DNA, and even chromosomal DNA. ... The low cost alternative Sybr safe is a safer option when looking to stain gels for DNA visualization.
