[Posted and mailed]
I don't have an answer to your problem as such, but these fat bands can be a
symptom of overloading the gel.
I am not sure I understand why the first loads should be overloaded and
not the second, but you could try loading less sample.
Hope this helps.
In article <9f6opj$qkf$1 at mercury.hgmp.mrc.ac.uk>,
"McNeely, Suzanne" <suzanne.mcneely at invitrogen.com> writes:
> We run a small core facility using a 377 sequencer. Lately we have begun to
> notice a pattern developing where our samples in even lanes do very well but
> the samples in the odd lanes are very poor. It appears that the first 300
> bps or so the peaks are broad and run over each other, after that the data
> seems normal. We tested this by running the same sample in both the even and
> odd lanes and the evens look good and the odds are bad. We run a 4.5% LR gel
> overnight(10hrs). We heat the samples for two minutes prior to loading and
> place on ice. We load the odds first, prerun for 2 minutes and then load the
> evens. This is our standard procedure and has been for the past two years.
> Has anyone seen anything like this? Any suggestions as to what might be
> causing this phenomenon?
Mouse Sequencing Group leader UK-HGMP
m.botcherby at hgmp.mrc.ac.uk
Tel:01223 494555 Fax: 01223 494512