microarray data analysis

Question

[au.rinki.bio]

hello, i am working on microarray data set and trying to find out differentially expressed genes. i have normalize microarray data using rma algorithm. i want to calculate fold change for selection of differentially expressed genes. rma algorithm give log2 transformed value, i am not confirm. then how i can calculate fold change?

[cpad0112]

FYI, Intensity values are log transformed in last step of RMA i.e summarization.

Answer 1

[venu]

Most normalization algorithms (all ?) give log2 expression value 0-16. You can use these values to find differential genes implementing methods like limma. You might be interested to check following links

• Analysing Microarray Data In Bioconductor
• limma userguide