How to analyze DNA electrophoresis bands?

1.
Smile-shaped zone (both sides are upturned, and the middle is concave):

Cause of formation: It is mainly caused by uneven solidification of the middle part of the gel, which mostly occurs in thicker gels
.

Solution: Wait until it is fully solidified before doing the experiment
.

2.
Frowning-shaped zone (both sides down, bulging in the middle):

Reasons for formation: Mainly appear in the protein vertical electrophoresis tank, which is generally caused by the air bubbles in the bottom gap between the two plates not being cleared
.

Solution: You can add an appropriate amount of buffer between the two plates to eliminate air bubbles
.

3.
Zonal tailing:

Reasons for formation: mainly caused by poor sample dissolution or excessive separation gel concentration
.

Solution: Centrifuge before adding samples; select an appropriate sample buffer and add an appropriate amount of sample solvent; leave the electrophoresis buffer for too long and re-constitute; reduce the gel concentration
.

　　4.
Texture appears in the zone:

　　 Cause: Mainly caused by insoluble particles in the sample
.

　　 Solution: Centrifuge before adding sample, add appropriate amount of sample to promote solvent
.

　　Five, ghost belt:

　　 Cause of formation: It is mainly because the reducing agent is oxidized and loses its activity during the heating process, which causes the original dissociated protein molecules to refold and combine and subunits to reassociate and polymerize into macromolecules whose molecular weight is larger than the target zone.
Sometimes can not enter the separation glue
.

　　 Treatment method: add proper amount of DTT or Beta mercaptoethanol after heating and boiling to supplement the insufficient reducing agent; add proper amount of EDTA to prevent the oxidation of the reducing agent

　　Six, bromophenol blue can not play an indicating role:

　　 Reason for formation: In experiments, we often encounter the phenomenon that bromophenol blue has run off the bottom of the plate, but the protein has not yet run off, which is mainly related to the concentration of buffer and separation gel

　　 Solution: Replace the buffer with the correct pH value and reduce the concentration of the separation gel

　　Seven, the zone is very thick:

　　 Reasons for formation: Mainly because the concentrated glue is not concentrated well

　　 Solution: Properly increase the length of the concentrated gel to ensure the correct pH (6.

　　8.

　　 Reasons for formation: Mainly because the electrophoresis tank is not properly assembled and the current does not form a path

　　 Solution: The electrophoresis tank is correctly assembled