Thomas J Stelick wrote:
>
> hello,
> We have been getting some inconsistant results on some of our sequencing
> and one problem may be the lot of big dye. The problem showed up around
> the time we started using a new lot. The lot # is 0101047. Is anyone else
> having problems. We are using a 3700. Or is anyone having a problem with
> pop-6 polymer lot # 0101130.
We have been questioning POP6 lot 0101130 ourselves. An instrument that was
working very well with read lengths of 700-800 suddenly changed to reads of
350-450 after only a POP6 lot switch. ABI had no other reports of a problem
with that lot.
There were reasons to suspect other problems: perhaps a bad array (regenerate
array improved the situation and switching arrays got us up to 650 nt reads)
and perhaps an instrument problem (we started seeing strange drop-outs in the
array image data in caps 90-96).
The symptoms after the POP lot change were (i) decreased resolution - broad
run-together peaks, (ii) *leading*-edges of peaks had reverse "tails" (did
that make any sense? I can't figure out how else to describe it) and (iii)
numerous capillaries suddenly gave no resolution at all. With such a routine
procedure as POP lot change, I can't image what we could have done that would
have toasted the array. I am still highly suspicious of the POP6 lot.
To re-iterate, yes we were suspicious of POP6 Lot 0101130, but no, we could
not prove it was a bad lot, and it is currently giving us modest resolution
but NOT great. I would be very interested in hearing of others using that
lot of POP6 and what results they are achieving.
Bob Lyons
University of Michigan
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