[BioC] Extracting Single Channel Intensities in limma

michael watson (IAH-C) michael.watson at bbsrc.ac.uk
Fri Oct 1 13:35:05 CEST 2004


Hi

I have performed print-tip loess normalisation followed by quantile
normalisation in limma.  I have then converted the resulting MAList
object back to an RGList object using RG.MA().  I now want to extract
the single channel intensities from this normalised RGList object to
create *new* RGList objects which represent comparisons between samples
that were not made on the arrays directly.

However, as RG.MA gives me log2(intensity) back rather than raw
intensity, I presume I need to un-log this data before sending it down
my normal analysis pipeline of RGList -> MAList -> lmFit(MAList) ->
eBayes() -> topTable() ??

Thanks
Mick



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