Dear members I am trying to check a procedure to identify outliers and natural clusters in microarrays. I have used standard yeast data from Saccharomyces, but they do not have truly outliers. Can anyone indicate me where can I find a database in R or BioConductor which contains outliers? Thank you very much -- jm~ _______________________________ Juan Miguel Marin http://www.est.uc3m.es/jmmarin Dep. of Statistics University Carlos III of Madrid Spain (E.U.)

JUAN MIGUEL MARIN DIAZARAQUE wrote: > Dear members > I am trying to check a procedure to identify outliers and natural > clusters in microarrays. I have used standard yeast data from > Saccharomyces, but they do not have truly outliers. > Can anyone indicate me where can I find a database in R or BioConductor > which contains outliers? I'm not sure what you mean by outliers, but there are currently >173,000 arrays of data in NCBI GEO (http://www.ncbi.nih.gov/geo). You can use the GEOquery package to get these data into Bioconductor. Also, you might want to look at the copa package, as it is specifically designed for looking for outliers in expression data. Sean