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Dipl.-Ing. Johannes Rainer
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@dipl-ing-johannes-rainer-846
Last seen 10.2 years ago
hi,
i am wondering how the annotation of the Affymetrix chips are done...
i
know how the AnnBuilder package works and i also used it, but as the
starting point for any annotation is the GenBank id for which the
probe
set codes i would like to know from where this mapping information
comes. are those packages built using the probe set to genbank mapping
that can be downloaded from affymetrix, or the (sometimes) newer
annotation that is available through Affymetrix NetAffx or some other
source?
I am really interested in this, because we got a little annotation
problem with the annotation for the hgu133plus2 chip (version 1.7.0).
one of our interesting genes in our study was the probe set
208078_s_at
which is mapped using the hgu133plus2 package (and the annotation from
Affymetrix) to NM_030751 (TCF8). we made real time PCR to confirm its
regulation but this TCF8 was not regulated at all. so i went back to
NetAffx tool and saw that Affymetrix gave a new annotation for this
probe set, all 11 probes perfectly match with the gene NM_173354
(SNF1LK) (i wonder how Affymetrix could annotate this gene to the TCF8
gene).
if the annotation packages are built using the downloadable probe set
to genbank mapping files from Affymetrix (which may never updated and
corrected for errors by Affymetrix) i believe that there may be more
annotation errors in this package like the one we found.
cheers, jo