The bands of DNA electrophoresis can only be seen under ultraviolet light. The principle of DNA electrophoresis is that DNA fragments of different lengths migrate to different distances in the agarose gel under the same electric field force. The smaller the length, the greater the migration distance. The faster the distance, which means the smaller the fragment is, the lower it is in the glue.

Generally, when running DNA electrophoresis, in addition to the sample, you also need to click on a marker. It is composed of several DNA fragments of known fragment sizes. Using the DNA electrophoresis strip as a reference, you can roughly determine the DNA fragments in the sample. size. And because the dan fragment in the marker is also quantitative.

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Generally, a 0.5cm wide comb can add 0.5g of DNA. The amount of sample added is based on Depends on the size of the well and the number and size of fragments in the DNA. When the sampling hole is large, the sample loading amount should be increased accordingly, otherwise the bands will be shallow or even unclear. On the contrary, the sample loading amount should be appropriately reduced, but loading too much sample will cause the sampling hole to be overloaded. This results in tailing and smearing, which is more pronounced for larger DNA.

The salt concentration in DNA samples will affect the mobility of DNA. Parallel control samples should use the same buffer conditions to eliminate this effect. DNA mobility depends on the concentration of the agarose gel, the shape and size of the migrating molecules.

It is possible to resolve a wide range of DNA molecules using gels of different concentrations. The concentration of the gel can be determined according to the range of DNA molecules in preparing agarose gel. Polyacrylamide gel electrophoresis should be used for small fragment DNA electrophoresis to improve resolution.

Baidu Encyclopedia-Electrophoresis Strips