GEL ELECTROPHORESIS

=Gel Electrophoresis= DNA is slightly negatively charged (due to the phosphate groups in its back-bone). When placed in an electric field, DNA will move towards the Cathode (positive terminal). Smaller fragments of DNA can move faster through a porous gel, allowing scientists to separate out different sized fragments according to the distances they travel. Often fragments of known sizes will be placed in one of the wells, giving a pattern or “ladder” that acts as a reference point. Unknown fragments can then be compared to this ladder in order to estimate their size. [image:http://i.imgur.com/Qw0460V.png]