Reasons for gel samples running unevenly?

Deanne Bell dbell at
Thu Aug 15 12:01:56 EST 2002

in general, this problem is usually due to a gradient in resistance or current across the gel

Many things can cause a change in resistance, some of them we have already mentioned:
:> :. . . different salt content in different wells?
:> :or a bubble under the gel (causing local heating)?
:> or pouring the  gel on an uneven surface so that one side of 
:the gel is "thinner" than the other

:What makes a good and what a poorly made electrophoresis apparatus?

If the apparatus is somehow responsible for an electrical current or heat gradient within the gel.

for example:
:> :a non-level apparatus OR CHAMBER, causing higher current flux in the 
:"shallow" side of the electrophoresis chamber

or, as you have asked, "The power supply sockets for the gel apparatus are both on the right.  - maybe this is heating up one side of the chamber more than the other side.

hope this helps
Deanne Bell
USDA Agricultural Research Service
9611 South Riverbend Avenue
Parlier, CA 93648
(559) 596-2806  voice
(559) 596-2791  fax
dbell at

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