At equivalent molecular weights, RNA will migrate faster than DNA. However, both RNA and DNA have a negative linear slope between their migration distance and logarithmic molecular weight. That is, samples of less weight are able to migrate a greater distance. This relationship is a consideration when choosing RNA or DNA markers as a standard.
When running RNA markers and RNA samples on a gel, it is important to prevent nuclease contamination, as RNA is very sensitive to ribonuclease (RNase) degradation through catalysis. Thus, all materials to be used in the procedure must be taken into consideration. Any glassware that is to come into contact with RNA should be pretreated with diethylpyrocarbonate (DEPC) and plastic materials should be disposable.