Why DNA fragments migrate slower than normally in capillary

Barbara Simionati bmr at mail.cribi.unipd.it
Thu Dec 14 10:50:31 EST 2000


I would like to know if someone knows the precise reason for what we
call "wide peaks", that is when fragments migrate slower than normally
in a capillary sequencer.

We have a sequencing facility and this appens for 2 or 3 samples every
96 samples of our customer (our project sequences do not have this
When we reload these samples, the sequence is always good and the
problem seems to be disapperared.
My hypothesis is that there is something in the DNA that is loaded in
the first injection.
In the second injection the contaminant is now under a hypotetical
threshold, so that its presence influence no more fragment migration.
Does someone know what could be the contaminant?
chaotropic salt from DNA binding to glass fiber, ethanol left in the
sample after washing, else.

Thanks in advance

Barbara Simionati

Sequencing Core
.BMR - Bio Molecular Research
CRIBI Biotechnology Centre
and Department of Biology
University of Padua, Italy


More information about the Autoseq mailing list

Send comments to us at biosci-help [At] net.bio.net