We have come across a strange phenomenon: On our latest
autorads some bands appear across all four lanes on the
For these reactions, a PCR product (which had been sequenced
succesfully before), was sequenced with eight primers (four
on both strands) using the Sequenase PCR product direct
sequencing kit (Amersham).
Other DNAs have been already sequenced in this domain with
the same primers, and did not show this phenomenon. After
comparing the old and the new autorads it is clear that it is
the G bands that appear in four lanes!
However, after about five hours of migration, these G bands no
longer appear in all four lanes and the final part of the sequence
can be read as normal.
Reactions have been made following the protocol described in
the Sequenase booklet, with a new stock of sequenase version
2.0 freshly diluted in a glycerol dilution buffer.
I did not find any specific answer to this problem in the
booklet, and therefore I am now looking for some help and
advice from anyone who as had this problem before.
Thanks for any reply!
Scientific and technical services Department
Royal Botanic Garden Edinburgh
e.mail: C.GUIHAL at rbge.org.uk