Sequence help

"Alexander Kraev" bckraev at bckraev at wawona
Mon May 8 10:16:23 EST 1995

In article <swkullman-0705951238590001 at>, swkullman at (Seth W Kullman) writes:
>Im looking for help from any one who has experience running sequence gels.
>Specifically my problem, my gels are running unevenly, with the outer sets
>of lanes running much faster than the inner sets, resulting in a
>"frowning" (upside down smile) rather extensive at times. 

Your spacers must be leaking at the bottom, i.e. they contain some gel
between the spacer and the glass plate. Try to place one pair of clamps
very close to the bottom edge of the gel. Another possibility is that
there is a thin "channel" of buffer alongside the spacer, which has a
higher conductance and a higher current through it generates more heat than
the current going through the gel, causing the "inverse smile". You can try
to squeeze some gel at the top beside the spacer to plug this channel. 
To avoid the formation of such channels, your may try using slightly more 
TEMED for polymerization and/or meticulously clean the spacers ( particularly 
from grease ). Hope this helps,

Alexander Kraev, Ph.D.                 Internet: bckraev at
Lab. of Biochemistry III               Phone: 0041-1-632-31-47
Swiss Federal Institute of Technology  FAX:   0041-1-632-12-13
CH-8092 Zurich
"Some ideas are obscure not because they are complex, but because they 
 are excluded from our circle of comprehension" - Kozma Prutkov

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