[BioC] GCRMA/RMA bimodal distribution

Matthew Hannah Hannah at mpimp-golm.mpg.de
Wed Aug 25 16:49:10 CEST 2004


Hi,

This has been mentioned before in the context of rma and that it was an
artifact of BG correction.

http://files.protsuggest.org/biocond/html/5066.html

I was very suprised to see that gcrma also gave a very pronouned bimodal
distribution. When comparing samples, obviously the relative positions
of the 2 peaks may influence observed expression changes. Would such
peak shifts be more likely in divergent samples, and if anyone wants to
comment on those.... ;-)

This example is using 12 chips (biological reps). But I initially
noticed it using 3 and 6 chips in rma.

Hope attachment works.

Cheers,
Matt


-------------- next part --------------
A non-text attachment was scrubbed...
Name: gcrma_dist.png
Type: image/png
Size: 6633 bytes
Desc: gcrma_dist.png
Url : https://stat.ethz.ch/pipermail/bioconductor/attachments/20040825/083e56a5/gcrma_dist.png


More information about the Bioconductor mailing list