Unadjusted graphs of expression for examples of genes identified in this study. Arrays are plotted along the x-axis, and expression (average difference) is plotted on the y-axis. Below the x-axis of each graph is a schematic of the corresponding template. (a) Two typical examples of high-scoring genes showing strain-specific variation. (b) A gene identified by Sandberg et al. as having strain-specific variation, for comparison with (a). We gave this gene a much lower ranking than the genes shown in (a). (c) Three high-scoring genes showing hippocampus enrichment. (d) Four high-scoring genes showing midbrain enrichment.