Entering edit mode
Dr. Smyth,
Thanks a lot for your important message! I did read your limma user
guide, and only found that "If there are multiple probe summary
profiles to be read, and the samples are summarized in a targets
frame, then the read.ilmn.targets function can be used." When I typed
?read.ilmn.targets in R, not much syntax showing up. I also read your
paper: Optimizing the noise versus bias trade-off for Illumina Whole
Genome Expression BeadChips. Nucleic Acids Research 38, e204. But I
did not find an example for that. Could you please let me know how
read.ilmn() reads multiple files and collate them.
For a beginner in microarray data analysis, it is so great to have
your help!!! Really appreciate it!
Thanks,
Xiayu
-----Original Message-----
From: Gordon K Smyth [mailto:smyth@wehi.EDU.AU]
Sent: Friday, June 28, 2013 6:46 PM
To: Rao,Xiayu
Cc: Bioconductor mailing list
Subject: RE: read.ilmn() and variation between chips
Dear Xiayu,
Genome Studio normally exports multiple BeadChips to the same probe
summary profile file. Our core centre normally exports all the chips
for each experiment to the same file. Even if you do have multiple
files,
read.ilmn() will read multiple files and collate them for you.
Have you read the documentation?
Best wishes
Gordon
On Fri, 28 Jun 2013, Rao,Xiayu wrote:
> Hello, Gordon
>
> Thanks a lot for answering my two questions. The information you
> provided was very important to us.
>
> One quick question, you said that read.ilmn() reads the files as
> output by Genome Studio without any need for intermediate
processing.
> What if I have so many samples from several chips, and I read in the
> data from each chip using read.ilmn(), and then I want to do
> comparisons based on all the samples? How to combine them?
>
> Really appreciate your kind help!
>
> Thanks,
> Xiayu
>
>
>
> -----Original Message-----
> From: Gordon K Smyth [mailto:smyth at wehi.EDU.AU]
> Sent: Friday, June 28, 2013 2:37 AM
> To: Rao,Xiayu
> Cc: Bioconductor mailing list
> Subject: read.ilmn() and variation between chips
>
> Dear Xiayu,
>
> Yes, it is good enough. neqc() has done between-array normalization
already, and there is no need for within-array normalization for
Illumina BeadChips.
>
> Please look at the help page
>
> ?neqc
>
> The read stages that you describe sound complicated. read.ilmn()
reads the files as output by Genome Studio at our core facility
without any need for intermediate processing.
>
> Best wishes
> Gordon
>
> -------------------- original message -------------------- [BioC]
> read.ilmn() and variation between chips Rao,Xiayu XRao at
> mdanderson.org Wed Jun 26 20:08:09 CEST 2013
>
> Hello,
>
> I have a question about background correction and normalization.
Please help me out! Thank you for your time!
>
> I have four chips of microarray experiments, and therefore four data
sets.
> I combined them together by merging on ProbeID and read in them as
one file using read.ilmn(), and I combined all the control probe files
into one and read it in. I just followed the limma user guide and use
neqc() for background correction and normalization. Is it good enough?
Do I need to consider within array and between array normalization?
>
> Thanks,
> Xiayu
>
>
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