What technique is used to separate DNA or protein fragments according to size and charge?

Gel electrophoresis is the technique used to separate DNA or protein fragments based on their size and charge. This method involves applying an electric field to a gel matrix, typically made of agarose or polyacrylamide. The negatively charged DNA or proteins migrate towards the positive electrode, with smaller fragments moving faster through the gel than larger ones. As a result, the fragments are effectively separated, allowing for analysis and identification based on their size.

This separation process is fundamental in various applications such as DNA fingerprinting, PCR product analysis, and protein characterization. It provides a visual representation of the different sizes of molecules, which can be further utilized in research, diagnostics, and various biotechnological applications.