>>> Ken Bialobrzeski <kbialo@MIT.EDU> 9/2/99 >>>
Hello out there. I was wondering if anyone has experienced what might be
called a "pinched gel" during dna sequencing? We use a 377XL ABI DNA
sequencer. The pinch occurs at the start of the gel so when the gel image
is pulled up the next day, the outside lanes at the bottom of the gel image
are "pinched" in. We still seem to track good data, but tracking the
outside lanes takes twice as long and some lanes even run into each other a
little bit. After researching this some, we know that excess salt must be
getting into the sample, but we use spin columns and have tried a wash
(using 100 ul mill Q water) with them before loading the samples onto the
beds and this doesn't seem to help. We receive samples from numberous
different users so the chance that the salt is from unproperly cleaned
templates seems nonexistent since we've been getting pinched gels for the
last 5 runs. Somehow, in our procedure, we must be introducing the salt to
the sample, but how? If anyone has any suggestions, it would be much
appreciated. I'm sure everyone can agree that saving time on tracking is
definitely a plus.
Regards,
Ken