DNA gels is a term that usually refers to agarose gels, made with TAE (Tris, Acetate, EDTA) or TBE (Tris, Borate, EDTA) buffer. They are the simplest to make and don't contain toxic compounds (unless EtBr is added to the gel).
YES!!You can use a simple Agarose gel to separate to view the DNA on electrophoresis. Use 0.8 - 1% gel for 5-10kbp , 2% for 0.2 - 1kbp.If the fragments are really tiny, use an Acrylamide gel...
Assuming you're talking about an electrophoresis gel for separating DNA: DNA is itself negatively charged because it contains phosphate groups. Thus, when you apply a current, it will move towards...