I'm in need for a set of highly expressed constitutive set of genes for an organism of interest. I found microarray data for my organism where they have done whole transcriptome profiling for finding differential expression between two developmental stages of the same organism.
I have downloaded the microarray dataset of my organism from NCBI GEO. I have a file that contains raw data and another file containing log normalized (processed) data of every gene in the organism. The authors in their papers have indicated that genes with log2 normalized ratios between 0.6 and 1.7 are supposed to be the constitutively expressed gene set. The genes lying in the given range can be extracted from the processed data file of log normalized values in these ranges.
But If I have to find highly expressed genes from this whole set of constitutively expressed genes,I require individual intensity of the genes from the raw data so that I can compare and find out highly expressing constitutive genes.
Is there any way to use the log normalized ratios to find absolute signal intensities of that gene? If so, how can it be done? Also, if I can find absolute intensities from the raw data, which column in the raw data file should be chosen?