Figure 1.

Variance of gene expression relative to transcript abundance. Standard deviation versus average transcript abundance of approximately 47,000 probe sets across 5014 AffymetrixHuman133 2.0 arrays. Spots in blue show probe sets with Present calls in at least ten percent of arrays, while spots in red are those with Absent calls in more than ninety percent of arrays. The probe sets contained between the square brackets are highly enriched in ribosomal protein genes, but include many of the commonly used reference genes (e.g. GAPDH, ACTB, B2 M, PPIA, EIF1, ACTG1, UBC, EEF1G, TUBA1B, EEF1A1, TPT1).