Global comparison of expression profiles between rat strains/lines. (A) The total number of genes affected by TCDD treatment in each rat line or strain is compared at levels of statistical significance (adjusted p-values; -log10) ranging from 0 to 5. (B) Hierarchical clustering with within-row scaling of all non-constant genes (variance > 0.1). Within the heatmap, blue indicates genes induced (up-regulated) by TCDD; red indicates genes repressed (down-regulated) by TCDD. Within the annotation bars (right side of heatmap), red indicates which rats were exposed to TCDD and white indicates those exposed to corn oil vehicle. The first column of annotation bars indicates the strains/lines of animals profiled: yellow, L-E; light blue, LnC; green, H/W, dark blue, LnA. The colour-scale gives within-row-scaled expression values, with red hues indicating low-expression and blue hues indicating high-expression.