Slanted Bands on Agarose Gels

[Dave Harry]

>: Has anyone experienced bands(DNA) that run slanted on an agarose gel? -
>: i.e. the bottom of the EtBr stained frag. of DNA seems to be migrating
>: faster than the top.  This phenomenon occurs with all samples on the gel
>
>	I would suspect a difference in buffer strength between gel and 
>running buffer.  Try immersing your poured gels in running buffer for a 
>few hours before the run.  I usually pour a few gels at a time and then 

I too have experienced the "slant" problem at times, and haven't figured
it out.  I doubt the buffer gradient idea in that I routinely make up my
gels in the exact same buffer used to run them (always 1x TBE).  But I
can't discount a residual pH change from the preparation of the gel
itself.  

I'm curious--do you happen to pour your gels in the cold, and are they
high concentrations of agarose?  I've suspected this intermittent problem
occurs more often for me when using 2% agarose gels poured in a coldroom
(when I'm impatient for the result). 

Just a thought...

David Harry                       Institute of Forest Genetics
deh at s27w007.pswfs.gov             USDA Forest Service, Pacific SW Station
Phone:  510/559-6439              PO Box 245
FAX:    510/559-6499              Berkeley, CA 94701