Standard procedure in R for pre-processing of Affy .CEL file
Modified from Soumyaroop Bhattacharya (sbhattacharya@rics.bwh.harvard.edu) 's post at http://lungtranscriptome.bwh.harvard.edu/Microarray%20Data%20Analysis%20using%20Bioconductor.pdf .
Using affy package
Save all the .CEL files for the analysis and the corresponding .CDF file for the particular array in one directory. If you are connected to internet then R will get .CDF file. Run R from that irectory.
In R write
1. RMA
3. MAS 5.0 Expression Intensities (http://www.affymetrix.com/analysis)
Using affy package
Save all the .CEL files for the analysis and the corresponding .CDF file for the particular array in one directory. If you are connected to internet then R will get .CDF file. Run R from that irectory.
In R write
- library (affy)
- Data <- ReadAffy() # Reads in Data
1. RMA
- eset <- rma(Data)
- eset <- expresso (Data, normalize.method=”quantile.robust”, bgcorrect.method=”rma”, pmcorrect.method=”pmonly”,summary.method=”medianpolish”)
- write.exprs(eset,file=”myDataRMA.txt”)
- eset <- expresso (Data, normalize.method=”invariantset”, bgcorrect=FALSE, pmcorrect.method=”pmonly”, summary.method=”liwong”)
- write.exprs(eset,file=”myDataDChip.txt”)
3. MAS 5.0 Expression Intensities (http://www.affymetrix.com/analysis)
- eset <- mas5(Data)
- eset <- expresso (Data, normalize =FALSE, bgcorrect.method=”mas”, pmcorrect.method=”mas”, summary.method=”mas”)
- write.exprs(eset,file=”myDataMAS5.txt”)
- Calls <- mas5calls(Data)
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