Hierarchical clustering of genes that show differential expression in the FC of PSKO and CNT mice. The numerical data are presented in Additional File 4. Gene probes are clustered in rows (denoted by symbols and probe identifiers), microarrays are clustered in columns (denoted by sample identifiers). Each pixel represents a single, color-coded gene expression value form FC form a PSKO or CNT mouse sample at five developmental ages. Shades of red correspond to the magnitude of expression increase, the intensity of blue corresponds to the magnitude of the reduction in gene transcripts. Note that the frontal cortical PSKO and CNT samples, regardless of developmental age, cluster on different ends of the dendrogram.