[BioC] info su illumina

Lynn Amon lynnamon at u.washington.edu
Tue Mar 7 02:11:31 CET 2006

Hello Mark and Giovanni,
Mark is correct that you need to make the changes to the Settings.xml 
file BEFORE you scan the beadchip.  So you might want to do it the next 
time just to have the data should you decide to use it.  It would be 
nice to normalize at the bead-level but I have had trouble with R and 
Windows and memory limits when I try to do much with beadlevel data and 
more than a few arrays.  Right now, I just read in the bead-level data, 
summarize it by probe and then throw away the bead-level stuff.  Does 
anyone have any suggestions on how to get around these memory issues?  I 
have the same problem with Affy data unless I use RMA.

Lynn Amon
Research Scientist
Department of Pathology
University of Washington

Mark Dunning wrote:
> Hi Giovanni,
> You will be able to analyse this data using 'beadarray'. The package is able
> to read bead-summary data which has been processed by BeadStudio (a single
> averaged value for each bead type on an array) or the bead-level data. If
> you make the modifications that Lynn suggests you will able to extract
> intensities of each bead using the scanning software. It does not sound like
> you have these files though. However, to make full use of the beadarray
> package you would also require files which give the coordinates of each bead
> on each array. Unfortunately, Illumina seem quite reluctant to give out the
> bead centre coordinates at the present time. We are however pressing them to
> make this information available.
> I think the best way for you to proceed would be to read the file
> geneprofile.csv into beadarray. The quickest way to do this is to put the
> file in a directory on it's own, change the R working directory to point to
> this and use the "readBeadSummaryData" command from beadarray. You will
> probably need to use the columns parameter to specify the names of the
> columns that are being used in the file. I believe the following command
> will work for the standard output from BeadStudio
> BSData = readBeadSummaryData(columns=list(ProbeID="TargetID",
> AvgSig="AVG_Signal", Nobeads="Avg_NBEADS", BeadStDev="BEAD_STDEV", Detection
> ="Detection"))
> This will then create a list object similar to the RGList object used in
> 'limma', ie the expression values are in the $R matrix with rows
> representing genes and columns representing arrays. This expression matrix
> can be used for clustering, pca, linear modelling (via limma) or
> normalisation. So far we provide median, quantile or qspline normalisation -
> although methods within the 'affy' package could also be used. Additionally,
> the 'plotMAXY' function will give scatter and MA plots for multiple arrays
> and is a useful way of judging array quality.
> btw do you know how the data in geneprofile.csv was normalised by
> BeadStudio? Illumina recommend a rank invariant normalisation plus
> background correction, but that seems like a very bad idea to me looking at
> some of the data it produces!
> Please let me know if you have any further questions or comments. The
> package is still in the development stage, so feedback is very much
> appreciated :)
> Regards,
> Mark
> -------------
> Mark Dunning
> PhD Student
> Computational Biology Group
> Hutchison / MRC Research Centre
> Department of Oncology
> University of Cambridge
> Hills Rd, Cambridge CB2 2XZ
> -----Original Message-----
> From: bioconductor-bounces at stat.math.ethz.ch
> [mailto:bioconductor-bounces at stat.math.ethz.ch]On Behalf Of Giovanni
> Coppola
> Sent: 04 March 2006 16:54
> To: Lynn Amon
> Cc: Bioconductor
> Subject: Re: [BioC] info su illumina
> Hello Lynn,
> I am trying to analyze Illumina (Sentrix BeadChip Mouse Ref8) data
> with the beadarray package.
> All I have is:
> 1) a geneprofile.csv (matrix with expression values)
> 2) for each array strip, three files (.idat, .jpg, .xml)
> 3) one .sdf file
> 4) metrix.txt
> 5) the illumina CD with beadmap files
> 6) one copy of the BeadStudio software
> I assume I can't use the beadarray package, is that correct?
> Can I use the BeadStudio software to obtain bead level text files?
> Thanks
> Giovanni
> On Feb 8, 2006, at 10:18 AM, Lynn Amon wrote:
>>One possibly helpful note about Illumina arrays is that you need to
>>a change to the Settings.xml file in the ProgramFiles/Illumina/
>>directory in order to get summary or bead-level text files which can
>>then be read in using read.table or with the beadarray package.
>>Change the line:  <SaveTextFiles>false</SaveTextFiles> to
>>and add the following line if you want bead-level data:
>>Keep in mind that the bead-level files are large especially for the
>>whole genome chips.
>>Lynn Amon
>>Research Scientist
>>Department of Pathology
>>University of Washington
>>Bioconductor mailing list
>>Bioconductor at stat.math.ethz.ch
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