Question

In Gel Electrophoresis, why does volume of your control have to be the same as your test solution?

Answer 1

Because the effect is dependent on the volume of the gel.

Explanation:

Gel electrophoresis is an effect of electric charge on particles across a particular volume of liquid and pore size (the gel). If the control does not have the same dimensions, the effective electrical field gradient will be different. That would invalidate the "control" as a control system.

Example:
http://www.assay-protocol.com/molecular-biology/electrophoresis/agarose-gel-electrophoresis