Entering edit mode
Dear Tiandao,
Dealing with multiple gal files is very tricky, but possible. In
limma, you need to read in the GPR files for each GAL file
separately, identify control spots separately, and normalize
separately. So, if you have two GAL files, you will end up with two
normalized MAList objects MA1 and MA2.
You will then need to align MA1 and MA2 by gene ID. There is a merge
command, but very often the situation is too complex for this command
to handle. Usually you will need to remove the control spots from MA1
and MA2 separately, to get down to a list of common genes, then sort
MA1 to match the gene order of MA2, then cbind them together.
If MA1 and MA2 are of the same length, with the same gene IDs, then
something like this wil do the merge:
m <- match(MA2$genes$ID, MA1$genes$ID)
MA <- cbind(MA1[m,], MA2)
There is any alternative method, which is to use the printorder()
function to map spots back to the original 384-well plate positions,
then align the arrays by 384-well plate. This method requires that
the plates were used in the same order throughout the printing,
except for control plates.
You need to be very careful!
Good luck.
Gordon
>Date: Sun, 9 Sep 2007 14:26:47 -0500 (CDT)
>From: Tiandao Li <tiandao.li at="" usm.edu="">
>Subject: [BioC] different gal files using limma
>To: Bioconductor_help <bioconductor at="" stat.math.ethz.ch="">
>Message-ID: <pine.lnx.4.64.0709091401440.32134 at="" orca.st.usm.edu="">
>Content-Type: TEXT/PLAIN; charset=US-ASCII
>
>Hello,
>
>I am analyzing cDNA microarray data using limma. I generated the GAL
file
>using the program coming with chipwriter, everything looks great.
However,
>when I printed the first batch of chips, after the last dip of pins
in the
>first plates, print, wash, and the pins redipped again in the first
plate
>from the beginning, and print, wash, then stop to change the plate.
The
>company gave us the patch to solve this problem. So this gal file is
a
>little different than the rest batches of chips, the locations of
genes,
>MSP, and controls are different (5%). After hybridization, I used
GenePix
>Pro 6.1 for spotfinding. After reading the data into limma, I want to
use
>MSP and control spots for normalization. I don't know how to label
>different gal files using readSpotTypes() in all chips.
>
>Thanks,
>
>Tiandao
>
>I am kind of new to R and limma. The following is my setting.
>
> > sessionInfo()
>R version 2.5.1 (2007-06-27)
>i386-pc-mingw32
>
>locale:
>LC_COLLATE=English_United States.1252;LC_CTYPE=English_United
>States.1252;LC_MONETARY=English_United
>States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252
>
>attached base packages:
>[1] "stats" "graphics" "grDevices" "utils" "datasets"
"methods"
>[7] "base"
>
>other attached packages:
> statmod limma
> "1.3.0" "2.10.5"
>
>Codes for analysis
>
>library(limma)
>
>A <- list(R="F635 Median",G="F532 Median",Rb="B635",Gb="B532")
>B <- list("Block", "Column", "Row", "Name", "ID", "X", "Y", "Dia.",
"F635
>Median", "F635 Mean", "F635 SD", "F635 CV", "B635", "B635 Median",
"B635
>Mean", "B635 SD", "B635 CV", "% > B635+1SD", "% > B635+2SD", "F635 %
>Sat.", "F532 Median", "F532 Mean", "F532 SD", "F532 CV", "B532",
"B532
>Median", "B532 Mean", "B532 SD", "B532 CV", "% > B532+1SD", "% >
>B532+2SD", "F532 % Sat.", "Ratio of Medians (635/532)", "Ratio of
Means
>(635/532)", "Median of Ratios (635/532)", "Mean of Ratios (635/532)",
>"Ratios SD (635/532)", "Rgn Ratio (635/532)", "Rgn R2 (635/532)", "F
>Pixels", "B Pixels", "Circularity", "Sum of Medians (635/532)", "Sum
of
>Means (635/532)", "Log Ratio (635/532)", "F635 Median - B635", "F532
>Median - B532", "F635 Mean - B635", "F532 Mean - B532", "F635 Total
>Intensity", "F532 Total Intensity", "SNR 635", "SNR 532", "Flags",
>"Normalize", "Autoflag")
>
># read 6 test files
>targets<-readTargets(file="targets.txt", row.name="Name") # 6 test
files
>RG <-
>read.maimages(targets$FileName,source="genepix",ext="gpr",columns=A,o
ther.columns=B)
>spottypes <- readSpotTypes("spottypes3.txt") # short spot types
>RG$genes$Status <- controlStatus(spottypes,RG)
>
>targets
>SlideNumber FileName Cy3 Cy5 Name
>1 13582917 N0 N1 N0N121
>2 13582918 N0 N1 N0N122
>3 13590446 N0 N1 N0N123
>4 13590420 N1 H1 N1H121
>5 13590521 N1 H1 N1H122
>6 13591193 N1 H1 N1H123
>
>spottypes3
>SpotType ID Color
>gene * black
>Calibration Calib* blue
>Ratio Ratio* red
>Negative Neg*|Util* brown
>MSP MSP orange
>Alexa Alexa* yellow
>blank NotDefined green