DNA electrophoresis


This simulation assumes that the loading dye is 50bp and the marker is 50bp. ('bp' is a unit showing the number of base pairs of DNA.)


Electrophoresis is a chemical phenomenon in which an electric charge in a solution moves toward an opposite electrode.
Swedish biophysicist Arne Tisselius devised electrophoresis during the study of blood proteins in the 1930s. Arne Tissellius was awarded the Nobel Prize in Chemistry in 1948 to contribute to an electrophoretic method.

Gel electrophoresis

Generally, DNA is electrically (-) polar, and when placed in an electric field, it moves toward (+) polarity. Using this property, fragmented DNA can be classified according to its length.
Briefly, the experiment method is as follows.

  1. DNA is extracted from the collected cells.
  2. The DNA is treated with restriction enzymes and divided into small pieces.
  3. If necessary, do 'loading dye' treatment. (It allows you to see the progress of electrophoresis with the eyes.)
  4. Place the DNA sample on the electrophoretic plate and connect the electrodes.
  5. When electrophoresis is complete, treat it with a fluorescent dye and then illuminate it with ultraviolet(UV) light.

The electrophoretic plate is made from agarose gel extracted from seaweed. The agarose gel is a net structure in which the threads are intertwined, so the larger the size of the solute passing through, the slower the gel passes. The shorter the DNA length, the more near the position from the (+) electrode.

There are two types of staining for observing DNA fragments: loading dye and fluorescence dye (UV dye).
Of these, "loading dye" is for observing progress. For detailed observation, fluorescence staining should be added after electrophoresis. When the UV lamp is illuminated, the fluorescent material converts the ultraviolet light into visible light, making it easy to observe with the eyes.