Gel electrophoresis

Gel Electrophoresis

A laboratory technique that separates DNA fragments by length using an electric current.

Agarose Gel

A semi-solid gel matrix immersed in an electrolyte buffer solution that holds the DNA samples in depressions called wells.

DNA Migration

Because DNA is negatively charged, it moves away from the negative electrode at the wells and toward the positive electrode at the opposite end.

DNA Fragment Separation

Smaller DNA fragments travel faster and farther through the gel than larger, slower fragments.

DNA Profile (DNA Fingerprint)

The distinct banding pattern formed on the gel after DNA fragments are separated and visualized.

Restriction Enzymes

Specialized enzymes used to cut DNA into specific fragment lengths before loading them into the gel.

DNA Ladder

A standard reference sample containing DNA fragments of known sizes, run alongside test samples to estimate their fragment lengths.

Loading Wells

Depressions at the negative electrode end of the gel where DNA samples and dye are carefully pipetted using fresh tips each time.

Electrophoresis Voltage & Timing

An electrical current of 80–150V is applied for 1–1.5 hours to allow DNA to migrate across the gel.

UV Light Visualisation

Fluorescently dyed DNA bands are exposed to ultraviolet light to make the fragment patterns visible for comparison