Hierarchical clustering of differentially expressed genes in phytol-treated compared with pristane-treated rats. Euclidean distance was used as a similarity measure. Each column represents one individual rat, and each horizontal stripe represents a gene transcript. The Affymetrix probe set identification, the gene symbol, the average fold change (FC) for phytol versus pristane together with the p value, and the average fold change for phytol/pristane versus pristane and its p value are given to the right. The colors in the clustering represent the gene-expression level in each individual rat compared with the average expression in all arrays, where green indicates low expression and red represents high expression.