Titration analysis of probe set response. Probe sets were selected for analysis based on the expression results detecting different transcripts. Probe sets were binned based on the fold change between samples A (universal reference) and B (total brain), and assessed for correct titration of expression values for samples A, B, C, and D. Probe sets were filtered statistically and those with p values < 0.001 were analyzed. Probe types were separated according to exon body and junction probes. The left graph indicates probe sets which were more highly expressed in sample A than sample B (A > B), and the right graph displays probe sets which were more highly expressed in sample B versus sample A (B > A).