Loading Dye

A colored buffer mixed with a DNA* or other types of samples before loading the samples onto a gel for electrophoresis. The dye contains a relatively high concentration* of either glycerol or sucrose. This makes the dye more dense than the surrounding running buffer* and causes the sample mixed with the dye to sink into the well when placed over the well with a pipette. The loading dye also contains a small amount of dye. Coloring the sample makes it easier to keep track of which wells contain a sample.