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Breuk102
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@breuk102-836
Last seen 10.2 years ago
Dear limma users and developers,
At our laboratory we analyze our MA data using limma. Currently we
have
created a dedicated array on which the same set of genes is spotted
three
times on one slide. Actually it is one design spotted three times. In
Imagene you can now create a META gid for (in this case) the 4*4
grids. This
grid you call grid A.. Then you can copy it several times (thereby
creating
metagrid B and C). You then end up after quantification with a large
imagene
file having the information of the three metagrids: (its like having
three
slides on one slide!)
e.g.
Field GridRow GridCol SpotRow SpotCol ID
A 1 1 1 1
Pp11
A 1 1 1 2
Pp12
..............
A 4 4 17 17
P..
B 1 1 1 1
Pp11
B 1 1 1 2
Pp12
..............
B 4 4 17 17
P..
C 1 1 1 1
Pp11
C 1 1 1 2
Pp12
..............
C 4 4 17 17
P..
When loading these files in either limma and limmaGUI only the A Field
is
read. Not the values belonging to the B and C metagrid (which are the
replicates).
Is there a simple way to solve this problem ? Or do I have to cut
these
files into three parts ?
Secondly, using limma and the targets <- readTargets function you
cannot use
the targets object directly in the read.imagene function. I solved
this
to create matrix with ncol=2 and nrow same as in the targets object.
Then
this can be used directly in read.imagene.
Next you would like to add color to your MA plots using controlTypes
and
Spottypes. This doesn't work either because when reading the imagene
data
files no columns RG$genes$Name and RG$genes$ID are created (actually
onlu
RG$genes[['Gene ID']] exists.. I solved this by : RG$genes$Name <-
RG$genes[['Gene ID']] and same for ID. Then you will be able to use
the
conrol types and colors for the colored MA plots.
The same problem applies for limmaGUI. If you do not have a GAL file
and
load the imagene files directly into limmaGUI you cannot assign colors
using
spotTypes either. (Error messages appear already after loading the
files).
I hope that the developers can implement these suggestions/workarounds
for
these problems ?
Yours, Bas van Breukelen
=================================
Dr. Ir. B. van Breukelen
PostDoc, Bioinformatics, Molecular genetics
Dept. of Biology.
Room N407: H.R. Kruytgebouw
Padualaan 8
3574 CH Utrecht
Tel: +31(0)30 253 3355
Mobile: +31(0)6 24 996046
e-mail: b.vanbreukelen@bio.uu.nl
website: http://genomics.bio.uu.nl/