Reasons for gel samples running unevenly?

[Paul Wary]

Michael Witty <mw132 at mole.bio.cam.ac.uk> wrote:
> On 14 Aug 2002, Paul Wary wrote:
> 
> > What reasons can there be for gel samples running unevenly?
> > For example, the same DNA marker on the left of my gel runs
> > differently on the right, i.e. the corresponding bands are not exactly
> > at the same places.
> > With many samples next to each other I can also see it by the
> > bromophenol blue band, which is not a straight line as it is supposed
> > to be.
> >
> > Paul
> >
> 
> . . . different salt content in different wells?
> 
> or a bubble under the gel (causeing local heating)?
> 
> or non-level apparatus, causing higher current flux in the "shallow" end?
> 
> Mike.

By non-level apparatus, do you mean a gel apparatus that causes a gel
to be thinner on one end than on the other?
Another observation I may add is that the samples on the left usually
run faster than the samples on the right, which I can see by a upward
curved bromphenolblue band. The power supply sockets for the gel
apparatus are both on the right. Can that be a factor?

Paul