Dear community,
I am currently trying to figure out this question. I have tried different keywords but I do not seem to find the right thread.
What I want to know is:
- Does limma arrives to a pvalue by using the log2 scale of the normalized array data?
- Does limma arrives to a pvalue using the normalized array data directly and then shows the differences as log2 fold changes in the top table?
If you know the proper thered to refer to, that will be of great help, else, I am grateful for your responses.
Thanks!
Thank you very much Aaron,
I normalized the array data with the RMA algorithm.
According to this thread, RMA log transforms the data:
log transform in RMA normalization
Yes, that's correct, the RMA algorithm returns values on a log scale.
Dear Aaron, I just see your post during browsing my issue. during miRAN (microarray) analysis with limma, I noticed that some miRNAs expressed only in treatment group, not control, actually they have the negative expression values in the control group. So, they tend to be interesting DE miRNAs. However, in the case of log2 transformation (after quantile normalization), these negative values converted to NA and don't consider for DE analysis, so we simply missed them due to log transformation. Could you please tell me your suggestion in this situation?
Please don't add comments to six year old posts. Start a new one, or if necessary add a link to an existing new thread.