1. How to minimize foaming of gel?

• When preparing agarose for electrophoresis, it is best to sprinkle the agarose into room-temperature buffer, swirl, and let sit at least 1 min before microwaving. This allows the agarose to hydrate first, which minimizes foaming during heating.

 

2. How to create sharper band?

• Loading DNA in the smallest volume possible will result in sharper bands.

 

3. How to preserve DNA in agarose gels for long-term storage?

• You can preserve DNA in agarose gels for long-term storage using 70% ethanol.

 

4. Why can't put too much buffer covers the gel?

• Migration of DNA is retarded and band distortion can occur when too much buffer covers the gel. The slower migration results from a reduced voltage gradient across the gel.

 

5. Why need to control the temperature of gel electrophoresis?

• Electrophoresing a gel too "hot" can cause the DNA to denature in the gel. It can also cause the agarose gel to deform. Cool the gel with a small fan during the electrophoresis.

 

6. What is the minimum amount of DNA detectable by ethidium bromide?

• The minimum amount of DNA detectable by ethidium bromide on a 3-mm-thick gel and a 5-mm-wide lane is 1 ng. Do not exceed 50 ng of DNA per band on a 3-mm-thick gel and 5-mm-wide lane.

 

7. Does buffer affects the resolution of DNA?

• Electrophoresis buffer can affect the resolution of DNA. TAE (Tris-Acetate-EDTA) buffer provides better resolution of fragments >4 kb, while TBE (Tris-Borate-EDTA) buffer provides better resolution of 0.1- to 3-kb fragments. In addition, use TBE buffer when electrophoresing >150 V and use TAE buffer with supercoiled DNA for best results.