Figure 1 From: 'Systems toxicology' approach identifies coordinated metabolic responses to copper in a terrestrial non-model invertebrate, the earthworm Lumbricus rubellus Hierarchical cluster analysis of samples according to fitted metabolite concentrations (scaled to unit variance). Samples 40_1r1 to 40_1r5 represent five instrument replicates, demonstrating that neither the machine variation nor the peak fitting procedure introduce significant amounts of error compared with the within-group biological variation.Back to article page