What is the working principle of DNA gel electrophoresis?

The working principle of DNA gel electrophoresis is based on the fact that DNA molecules carry a negative charge due to the phosphate groups in their backbone. Because of this negative charge, when an electric field is applied across the gel, the DNA molecules move towards the anode, which is the positively charged electrode.

In the gel medium, smaller DNA fragments can navigate through the gel matrix more easily than larger ones, allowing for the separation of DNA molecules by size. This movement toward the anode is a fundamental characteristic of DNA electrophoresis and is crucial for analyzing and visualizing DNA samples after separation.

Understanding this principle is essential for interpreting the results of gel electrophoresis, as it helps in determining the size of DNA fragments based on their position in the gel after the electrical current has been applied.