[BiO BB] GeneExpressionOmnibus(GEO) question
ilya.venger at weizmann.ac.il
Wed Oct 27 06:12:42 EDT 2004
I am in the process of building a local expression database for S.
cereveisiae. The best source of expression data I could find was GEO.
They state there that the data they present in GDS accessions is
normalized, but they don't explain how.
The GSMs of different contributors not necessarily match, and they
sometimes lack parts of the data. Also, if the raw data is submitted,
how come they don't show the measurements for both repetitions of each
gene in a cDNA array.
Another problem, is that although the GDS are claimed to be normalized
the sum of logs for all genes on a chip doesn't sum to 0.
So, if anybody worked with GEO before, and has experience at it I would
be glad to pose several more specific questions.
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