Why do the smallest fragments of DNA move the farthest during electrophoresis?

Electrophoresis is a laboratory technique for sorting DNA, RNA, and protein molecules according to their size and electrical charge. The molecules that will be separated through a gel are moved by an electric current. Smaller molecules can flow faster through the pores in the gel, which act as a filter.

The charge of the molecules influences the direction of movement, while their size and shape, the density of the gel, and the strength of the electric field influence the pace of movement.

Because DNA is a negatively charged molecule, when a current is supplied, it will flow toward the positive pole of the gel. When restriction enzymes break DNA, the different fragments will travel at different speeds. Because the tiniest fragments move the fastest, they will go the greatest distance during the current's duration.

Thus, DNA fragments will migrate from the anode to the cathode because DNA molecules are negatively charged due to the phosphate groups in their backbone. DNA segments that are shorter are lighter. As a result, they move through the gel faster and travel the furthest away from the wells.