The Lambda DNA Mono Cut Mix requires either Pulsed Field Gel Electrophoresis or, for regular gel electrophoresis, a very low percentage TAE agarose gel to effectively separate the fragments. Some common mistakes are running the gel too fast, using the wrong percentage of agarose, using the wrong buffer or loading too much of the marker.For the PFGE on a CHEF system, we recommend using a 1% agarose gel in 0.5x TBE buffer, which must be run with a cooling system, with pulse times ramped from 0.5 to 1.5 seconds, for 20 hours, 15C, 6V/cm (about 200V). For the conventional gel electrophoresis, use the following conditions: 0.5ug Mono Cut DNA, 0.4% agarose gel in 1x TAE buffer, 10V, room temperature for 24 hours. Basically, the gel must be run very slowly to achieve separation of the larger fragments. Adding Ethidium Bromide to the gel and the running buffer at a final concentration of 0.5ug/ml will effectively stain the bands during electrophoresis.