Hierarchical clustering of mean centered log2 normalized expression levels of cadmium and phenanthrene treated Folsomia candida. Heatmap view of mean centered expression levels by hierarchical clustering. Darker shading = higher expressions, lighter shading = lower expressions. Dendrograms show the relationships between the samples (columns) and genes (rows) by hierarchical clustering (average linkage of Euclidean distances). Abbreviations of the samples: cd = cadmium treatment, ph = phenanthrene treatment, c = control (water and acetone).