Smiles in agarose gels

Mr SMNN Faruque s.faruque at
Fri Feb 23 12:11:11 EST 1996

IMHO, smiling in agarose gels is often caused by distortion of the 
electric field by the samples.  
Samples loaded into the wells have a high resistance, but normally they 
do amount to a large barrier.  If a substancial cross-section of the 
electric field is blocked by the sample (ie  if wells are filled to the 
top, in a tank with only a small amount of buffer above the agarose, 
particularly when wells are joined to form a large well) frowning occurs 
(ie the centres of the bands are slower than the edges).

Now that I load my samples in 1x buffer (with 2.5% ficoll and some dye) 
I never see band distortion.


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