Thermo Scientific 6X DNA Loading Dye is used to prepare DNA markers and samples for loading on agarose or polyacrylamide gels. It contains two different dyes (bromophenol blue and xylene cyanol FF) for visual tracking of DNA migration during electrophoresis. The presence of glycerol ensures that the DNA in the ladder and sample forms a layer at the bottom of the well. The EDTA included in the solution binds divalent metal ions and inhibits metal-dependent nucleases.