What technique uses an electric field to separate DNA fragments?

Gel electrophoresis is the technique that utilizes an electric field to separate DNA fragments based on their size and charge. In this process, agarose or polyacrylamide gel serves as a medium through which the DNA molecules can move. When an electric current is applied, the negatively charged DNA fragments migrate towards the positive electrode. Smaller fragments are able to navigate through the pores of the gel more easily and travel farther than larger fragments, thereby allowing for the separation of DNA molecules by size.

This technique is essential in various applications such as DNA fingerprinting, restriction fragment length polymorphism (RFLP) analysis, and the verification of PCR products, making it a fundamental method in molecular biology and genetics.