Re: 373 Gel file corruption

Robert Lyons (boblyons@umich.edu)
Mon, 16 Nov 1998 11:57:43 -0500

Allison Pinder wrote:
>
> Subject: Time: 8:57 AM
> 373 Gel file corruption Date: 11/16/98
>
> Has anybody seen this one before? I have seen this about 4 times now: At the
> end of what appears to be a successful run, Data Collection will quit and
> SeqAnalysis 3.0 will launch. But before SeqAnalysis is completely run, the
> Mac will hang up and I will need to restart it to get it going again.
> Thereafter, I will be unable to open the Gel file and will get the error
> message, "Error -192, the required resources were not found". Geldoc does not
> help. Each time, I have not been able to recover the Gel file and the entire
> run has been lost. Now that its usually 64 samples that I'm running, this
> loss is just too substantial to tolerate. I run Norton regularly, but this
> continues to occur intermittantly. I have ftped such a file to Foster City
> but have recieved no insights thus far......frustration builds. Even if you
> have observed this phenomenon without knowing how to solve it, I would like to
> hear about it from you. Thanks!

Allison,
You probably can save those gels with a program called Gel Rescuer,
created by people at UT Southwestern. Check out the following web site:

http://gestec.swmed.edu/gestec2.htm

In general, your gel file needs its "resource fork" repaired. Macs
save files as two "forks", the resource fork and the data fork. The
data fork has all the scan lines themselves, while the resource fork
contains capsules of data that describe the sample sheet and tracking
info, among other things. You probably corrupted the resource fork
when the Mac crashed, but the scan data should be intact.
The rescue procedure involves creating a "dummy" gel file that
has all the required resource information. First, *** copy the Gel File
to a new name such as "bad gel file" ***. Set up Data Collection with
the usual settings and with the sample sheet set up as for the "bad"
gel file. Start collecting data, then after a few scan lines, stop
the collection process. You might as well interrupt the data analysis,
since there's no useful data to analyze anyway.
Gel Rescuer basically copies all the resources from the dummy gel
file to the "bad" gel file. Put the program and both gel files in the
same folder, and start Gel Rescuer. Follow its directions. When done,
your gel file should again be usable. Mac propeller-heads should
be able to do much the same thing with "ResEdit" (in fact, I often
copy new sample sheet information into a gel when the tech fails to
set it up correctly).

Good luck!

Bob Lyons
University of Michigan

-----------------------------
Robert Lyons, Ph.D.
Director, DNA Sequencing Core
University of Michigan
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