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Monnie McGee
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20
@monnie-mcgee-1106
Last seen 10.2 years ago
Dear BioC Users,
I am analyzing data from an AffyBatch object (that I've called
"allarray") with the following features:
> print(allarray)
AffyBatch object
size of arrays=1164x1164 features (63515 kb)
cdf=HG-U133_Plus_2 (54675 affyids)
number of samples=6
number of genes=54675
annotation=hgu133plus2
Note that there are no replicates in this array. In other words, the
6
samples are 6 different arrays with 6 different RNA treatments. I'm
trying to understand which genes are differentially expressed among
the
6 arrays.
I wanted to use RMA normalization, so I typed rma(allarray) and
received the following error
> eset1 <- rma(allarray)
Background correcting
Normalizing
Calculating Expression
Error in sigToEnv(signature, fdef) : Trying to get slot "signature"
from an object of a basic class ("NULL") with no slots
I tried to do the same thing using expresso and received the same
error. Here's what I typed and the response of bioconductor:
> eset1
<-
expresso(allarray,bgcorrect.method="rma",normalize.method="quantiles",
pm
correct.method="pmonly",summary.method="medianpolish")
background correction: rma
normalization: quantiles
PM/MM correction : pmonly
expression values: mas
background correcting...done.
normalizing...Error in sigToEnv(signature, fdef) : Trying to get slot
"signature" from an object of a basic class ("NULL") with no slots
I read an archived message with said that it was not a good idea to
use
median polish without replicated arrays, and that it would be better
to
use rlm. However, I can't seem to get an eset so that I can use rlm.
The funny thing is, just last week, expresso was working fine. I was
able to obtain an eset with no errors, using the same AffyBatch with
the same choices for all the methods.
I would appreciate some help.
Thanks,
Monnie