What is the loading dye for?
The loading dye, also referred to as the tracking dye, serves two functions. The first function is weight. The loading dye is made with a high concentration of sugar, which is heavier than the buffer solution in the tank. This causes the dye (and DNA contained within the dye) to sink to the bottom of the wells in the gel during the gel loading procedure. The second function is that it gives an indication of when to turn off the power to the electrophoresis chamber, since the DNA cannot be seen when the gel is running in the chamber. The dye moves faster than most of the DNA fragments. When the dye has reached the end of the gel, it is time to turn off the power.
