[BioC] methodological question
Phguardiol at aol.com
Phguardiol at aol.com
Sun Apr 20 11:59:24 MEST 2003
Hi,
Here is my question and I hope it fits into the BioC support group (!):
I have one cell line A with a deficient gene and another one B with the
corrected gene (same cell line indeed with gene transfered).
I have some Xpts conducted under normal cell culture conditions and some
others in which I have added a stressing agent - some at 10 nM and some
others at 100 nM ie 2 different concentrations -.
Let say the question is what are the genes that are differentially expressed
between A and B ?
I was planning to do a first comparison A vs B under normal cell culture
conditions, then a second for those ran at 10 nM of the stressing agent, then
a third one at the 100 nM dose...
But I was wondering if another one, pooling all the A chips versus all the B
chips -whatever the stressing agent is added or not and using the average
signal- should give me more power to detect some kind of differences because
of the increase number of chips in this case ? Said differently I guess it
might possible there to pick genes that have not been identified in any
previous comparisons just because of the lack of power / not enough chips ?
Then in this comparison could I say that I was looking for genes that are
differentially expressed between A and B whatever the conditions were, ie
with or without drug, means genes that are or seem to be invariantly
dysregulated in cells A ?
The other approach I see is to do all the first comparisons for each subgroup
and to do Venn Diagram Union: under normal cell culture conditions U drug 10
nM U drug 100 nM but then I am not taking the maximum power of the system
since I reduce the number of chips per comparison ?
It seems that another approach is proposed in T Speed book ie factorial
design Xpts but I m waiting for the book ?!
thanks for any help / advise
Philippe
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