Analysis of global gene expression in embryonic neural tissue. Analysis of global gene expression was performed using E13.5 DRG, E13.5 TG and E16.5 cerebral cortex samples. Only probe sets on the Affymetrix 430A array are shown, and transcripts with 'absent' calls in all three samples were excluded from the analysis. (a) Plot of DRG expression versus a replicate DRG assay closely approximates a diagonal line indicating equal expression in the two samples. (b) Plot of DRG expression versus the TG indicates very similar global gene expression in the two samples, with few points lying far from the diagonal. (c) Plot of DRG expression versus the embryonic cerebral cortex indicates a large number of transcripts that are differentially expressed between the two samples. Axis is graduated in log10 of scaled signal.