DNA Precipitating in Sequencing Gel
Dr M Fahmy
lsrge at csv.warwick.ac.uk
Tue May 30 06:49:59 EST 1995
My colleague has a problem that no-one here can solve.
After doing Ligation-mediated PCR on a genomic DNA sample, the dried pellet
is resuspended in sequencing stop buffer (95% formamide, 20 mM EDTA, + dyes),
denatured, chilled and loaded onto a standard 6% urea/TBE sequencing gel.
Although this was successful a while ago, the sample when loaded now
solidifies on contact with the buffer, at the top of the gel. This
has been repeated many times. All reagents have been changed apart from
some of the primers, the original genomic DNA sample and the tRNA for
precipitation. Sample remains OK if no PCR carried out.
Does anyone have any suggestions as to what is happening or how to
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