1. DNA Preparation:
- DNA is extracted from cells and then digested with restriction enzymes to create fragments of varying sizes.
- These fragments are then mixed with a loading dye, which helps visualize the DNA and track its movement during electrophoresis.
2. Loading Wells:
- The prepared DNA sample (with loading dye) is carefully loaded into wells at the top of the gel. These wells are small depressions created in the gel, typically near the negative electrode.
3. Gel Electrophoresis:
- The gel is submerged in a buffer solution within the electrophoresis apparatus, connected to an electrical current.
- DNA is negatively charged, so it moves towards the positive electrode at the other end of the apparatus.
4. Separation:
- The gel acts like a sieve, allowing smaller DNA fragments to move through it more easily than larger fragments. This results in the DNA being separated by size, with the smallest fragments traveling farthest.
Therefore, the DNA is loaded into the wells at the top of the gel, not directly placed into the electrophoresis apparatus.
