What makes gels smile?

Neil Winegarden nwinegar at credit.erin.utoronto.ca
Sun Dec 8 13:26:21 EST 1996


Matt thomas 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.
> 
> Any suggestions would be helpfull.
> 
> Thanks,
> Matt thomas
> Thomas at molbio.uoregon.edu

Well, in my experience I found that the smiling could be directly
correltated to wheter there was any ethanol left in the samples I
loaded. 
We made two gels (for primer extension analysis - UREA acrylamide gels),
each from the same batch of reagents, and loaded them with two sets of
samples.  The first set was dried down 30 minutes before loading, the
second 60 minutes.  The 60 minute samples were notacibly drier.  The 30
minutes samples smiled like a big 'ol happy face.  The 60 minute samples
ran perfectly straight.  Both gels were run in the same apparatus at the
same time, under the same conditions.

I don't know if this is the only cause, but once we started drying the
samples more, we eliminated the smiling problem.


		     ----------------------------------------
				Neil Winegarden
		     University of Toronto - Erindale College
			    Department of Zoology
		     email: nwinegar at credit.erin.utoronto.ca
		     ----------------------------------------



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