What makes gels smile?

Alexander Kraev kraev at bc.biol.ethz.ch
Sat Dec 7 12:15:43 EST 1996

In article <32A8CEAE.68E at molbio.uoregon.edu>, Matt thomas
<Thomas at molbio.uoregon.edu> wrote:

> Anyone have any ideas on how to prevent gels from smileling?  In 
> particular I'm talking about Urea/acrylamide gels, the kind typically 
> used for sequenceing.  I've heard all kinds of folk lore on this but 
> I'm interested in if anyone has a sure fire way to keep the smile from 
> happening.  
> I've tried running fast or slow, long or short prerunning times, long 
> or short polymerization times, but I haven't seen a real correlation 
> between all these.  

I don't know what do you mean by "folklore" because the phenomenon
appears to exist because the mobility is dependent on viscosity and the
latter changes with temperature. So, anything that makes this temperature
even across the gel width reduces or eliminates smiling. For practical purposes
the most straightforward, cheap and elegant way was and is to clamp two alumina
plates at both sides of the gel and determine at which POWER applied to the
gel  of given dimensions/resistance they are still effective.  Even the most
sophisticated machinery for automated sequencing costing over 100,000 US $
did not come much farther than this.

I hope this helps,

Alexander Kraev, PhD
Biochemie III, ETHZ Zurich
Phone 41-1-632-31-47
Fax 41-1-632-12-13
e-mail kraev at bc.biol.ethz.ch

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