I have a .CEL
file, need to be processed by affy
package. I get the corresponding probes and detection calls. I also want to calculate Pvalue of the .CEL
file.
I used the below code to get probes and detection calls and then combining:
##Read the CEL files (first command below) and then summarize and
##normalize with MAS5 (second command below)
affy.data = ReadAffy()
eset.mas5 = mas5(affy.data)
## getting the expression matrix (probesets/genes in rows, chips in columns).
exprSet.nologs = exprs(eset.mas5)
# Rename the column names if we want
colnames(exprSet.nologs) = c("Sample.1")
# Run the Affy A/P call algorithm on the CEL files we processed above
data.mas5calls = mas5calls(affy.data)
# Get the actual A/P calls
data.mas5calls.calls = exprs(data.mas5calls)
## Combining data
data.full <- cbind(exprSet.nologs,data.mas5calls.calls)
write.table(data.full, file="Full_data.txt", quote=F, sep="\t")
Here in the above code i also want to calculate the p-values and then want to combine.
.CEL
File:
CellHeader=X Y MEAN STDV NPIXELS
0 0 147.0 23.5 25
1 0 10015.0 1276.7 25
2 0 160.0 24.7 25
3 0 9710.0 1159.8 25
4 0 85.0 14.0 25
5 0 171.0 21.0 25
6 0 11648.0 1678.4 25
7 0 163.0 30.7 25
8 0 12044.0 1430.1 25
9 0 169.0 25.7 25
10 0 11646.0 1925.6 25
11 0 176.0 30.7 25
After getting probe Ids and expression value:
Probes Expression Value
1007_s_at 969.52517
1053_at 388.33007
117_at 628.92785
121_at 2254.15379
1255_g_at 156.56440
1294_at 659.27168
1316_at 381.76688
1320_at 89.60607
1405_i_at 304.36621
1431_at 165.30764
After calculating Calls ;
Probes Detection Call
1007_s_at "P"
1053_at "P"
117_at "P"
121_at "P"
1255_g_at "A"
1294_at "A"
1316_at "P"
1320_at "A"
1405_i_at "A"
1431_at "A"
How to calculate P-Values. ??
As per the data object used above: data.mas5calls
, you can try the following line of code.
assayData(data.mas5calls)[["se.exprs"]]
Output:
#1007_s_at 0.007542912
#1053_at 0.019303461
#117_at 0.011447358
#121_at 0.009985415
#1255_g_at 0.302547472
#1294_at 0.162935019
#1316_at 0.001141166
#1320_at 0.418069378
#1405_i_at 0.062021416
#1431_at 0.107301013