Help, decreasing temp. during long sequencing runs!

[Colin Rasmussen]

In article <3r2cqg$no0 at falcon.ccs.uwo.ca>, ovanham at julian.uwo.ca (o.  
van-ham) wrote:

> I've been finding that when I run my sequencing gel for relatively long 
> runs, the temperature (and current) steadily drops.  I've heard that this 
> is due to a pH change in the buffer (TBE).  Is this true?  If so, how do I 
> remedy the problem.  The situation is complicated by the fact that the 
> buffer is hot (P32) from the samples.
> 
> Thanks in advance for any suggestions.
> 
> Oded

You should run sequencing gels at constant power (watts) not at contant
current or voltage.  This will ensure a steady temperature during the
run.  If your power supply cannot be set to run constant power then all
you can do is put a thermometer on the gel plate and tweak the voltage
every now and then as you see the temp drop.

Colin