Gel Electrophoresis

Structure and procedure of the gel electrophoresis on the example of DNA

Gel electrophoresis is a method of separating and visualizing molecules.

Gel electrophoresis equipment consists essentially of a gel matrix that can be traversed by molecules. The gel matrix field is charged electrically. One side serves as a cathode (negatively charged) and the other side as an anode (positively charged).

Procedure of gel electrophoresis:

Molecules are of different sizes and therefore also differently strong or weakly charged, which is why they move further or shorter through the gel matrix according to their charge. In addition to the charge, the gel itself also influences how far the molecules move, because: in comparison to short molecules, they are more likely to be hindered from moving. In this way, molecules of the same size or the same charge store together in bands.

The DNA is now introduced into the matrix. Deoxyribonucleic acid is negatively charged with anions because of its phosphate and thus moves towards the anode.

Again to the general overview:

* Anions (negatively charged) migrate towards the anode (positively charged)

* Cations (positively charged) migrate towards the cathode (negatively charged)

When creating a genetic fingerprint, one uses gel electrophoresis:

Example 1 (criminal cases): If the DNA is extracted from a blood sample / sperm sample / skin cell found at the crime scene and compared with the potential offender, the band sequences would be identical in the event of a match.

Example 2 (paternity test): paternity tests can also be evaluated using the same procedure. The DNA of the candidate producer is compared with that of the child. Both samples are amplified by polymerase chain reaction (PCR) and visualized by gel electrophoresis. Although there is paternity, the pattern of the gangs will not be identical, but due to the relationship, there will be similarities in the gangs pattern.

Summary

Gel electrophoresis allows molecules to be separated and visualized in band patterns.

Similarly size molecules move approximately equidistant through the gel matrix, forming individual bands.

The method is suitable for comparing genetic material.