Fixing sequencing gels

John Nash nash at
Wed Nov 3 18:32:30 EST 1993

In article <CFxuKr.GFu at>,
the End <jgraham at> wrote:
>As it is virtually impossible to directly compare the same gel fixed and 
>unfixed, I was wondering why you felt it makes a difference ? I have 
>fixed some and not fixed others, and see no real differences. A collegue 
>here showed my two similar gels, one fixed and one unfixed, and there was 
>a barely perceptible softening of the bands on the unfixed RNA gel. I
>don't think it would in any way affect the data. Because of the extra
>time and wear on apparatus, I no longer fix.
>J. Graham

I don't fix, I just soak in water for 5 - 7 min.  If I soak for any
longer the bands DO become fuzzy.

A trick to stop your gel lifting off the plates is NOT to add the gel
to a tray full of liquid, but to add the liquid to the gel in the
tray, i.e. place the gel (on its plate) in a photographic or other
wide bottomed tray, gently pour the liquid into the tray, and keep
pouring very slowly until the gel is covered.  I've never lifted a gel
off the plate this way.  If a corner does lift, you can blow it back
with a lungful of air.

John Nash                           (nash at
Institute for Biological Sciences,  National Research Council of Canada,

      *** Disclaimer:  All opinions are mine, not NRC's! ***

More information about the Methods mailing list