[BioC] Beadarray expression data

Mark Dunning md392 at cam.ac.uk
Wed Aug 8 20:07:15 CEST 2007


Hi,

The beadarray package can read the output from BeadStudio version 3.  
In fact all you need to do is change the skip parameter so that it  
ignores the first 8 lines of output from BeadStudio 3 , which are all  
header information

The following function call should do the trick.

B = readBeadSummaryData(dataFile, skip=8, sep="\t")

When specifying the column names to read, you just need to specify  
the expression values are found in columns with the prefix  
"AVG_Signal". The function then searches through the column names and  
finds all instances of this string and creates an matrix with the  
appropriate number of columns.

Hope this helps,

Mark


On 7 Aug 2007, at 21:14, Ina Hoeschele wrote:

> Hi all,
>    I am completely new to the analysis of Illumina Beadarray gene
> expression data (but quite familiar with Affy data).  Such data (with
> samples run on 3 chips)  was sent to me by a collaborator. From the
> vignettes for Bioconductor packages 'beadarray' and 'BeadExplorer', it
> looks like these accommodate  Beadstudio version 1 and 2 data,  
> while our
> data was created by BeadStudio version  3.0.14.. Would it still  
> work? My
> collaborator sent two types of files to me: (1) a number of .csv files
> (read by excel, 2 for each sample) with columns Illumicode, N, mean  
> GRN,
> Dev GRN. (2) a summary .txt file with columns TargetID
> MIN_Signal-1814647013_A    AVG_Signal-1814647013_A
> MAX_Signal-1814647013_A    NARRAYS-1814647013_A
> ARRAY_STDEV-1814647013_A    BEAD_STDEV-1814647013_A
> Avg_NBEADS-1814647013_A    Detection-1814647013_A, with the
> MIN_Signal-... to Detection-... columns repeated for the remaining  
> samples.
> It looks like beadarray expects to read the summary data from a .csv
> rather than a .txt file? From the example given on page 2 of the
> beadarray vignette, the summary data are read in by
> BSData <- readBeadSummaryData(datafile, ..., columns = list(exprs =
> AVG_Signal", BeadStDev = "BEAD_STDEV", NoBeads = "Avg_NBEADS", ...)
>
> Since I have AVG_Signal-1814647013_A, AVG_Signal-1814647013_B etc. and
> not just one AVG_Signal, how do I specify the columns to be read?
>
> Sorry for these ignorant questions, but this is my first try at these
> data. Thanks for any advice!
> Ina
>
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