Non-denaturing gel

Also known as 'native' gel, non-denaturing gel is an electrophoretic gel used in polyacrilamide gel electrophoresis (PAGE). Detergents are used at a minimum to lyse cell membranes and no charged denaturing agents are used. The molecules being separated remain folded, however separation does not occur as predictibly as those run in a denaturing gel.

http://www.ap-lab.com/native_gels.htm