Sequencing gel question

[Alexander Kraev]

The original posting about how to get SHARPER bands was not specific
as to whether the bands were in fact UNSHARP or the author just wanted
to improve on his current results. There is, however, a rather
obscure reason why bands are sometimes fuzzy on sequencing gels, even 
with  the best chemicals.
The "smiling" effect PERPENDICULAR TO THE GEL SURFACE often causes fuzzy 
bands. This happens when there is a temperature gradient across the gel 
depth, i.e. when there is a strong air flow on the gel run in the hood. 
The best cure for this is to utilise an enclosure for the gel apparatus 
(= a box) and/or clamp TWO alumina plates to the gel. Commercial devices 
using one alumina backing may produce smeary bands when run in a good 
hood or in any other place with strong air currents.

Hope this helps,

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