Smiles in agarose gels

Dr.Sailesh Surapureddi SaiSu at MCB.LiU.SE
Tue Feb 20 01:23:57 EST 1996

>Hello everyone.
>	In order to separate DNA fragments obtained from RAPD, I make the 
>amplification samples run through an horizontal agarose gel. 
>Unfortunately, I always get this "smile" that bends all the bands and 
>makes the gel analysis much more complicated. The gels are 1,5%, and I've 
>tried different voltages from 20 to 80 volts, and although I noticed that 
>the "smile" is reduced with decreasing voltages, it isn't clear enough to 
>allow a perfect analysis. I'd be glad to hear any suggestion, advice or 
>magic trick to improve the situation.
>Thanks in advance.
>Pierre-Alexandre Landry
>Dept. des Sciences Biologiques
>Universite de Montreal
>C.P. 6128, succursale centre ville
>Montreal, Quebec
>H3C 3J7

Hi Landry:

Atleast some body is smiling! Be gald for it.

Coming to your problem, smiling of the gels usually occurs with improper 
castings, either the gel is being over or under boiled. I would check for the 
quality of the buffer too, incase it got contaiminated.

A through wash of the gel cast also helps to a lot greater extent.

Smile as you sail away.

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