Transcript profiles for copper exposed worms, transcripts selected on the basis of expected response to copper (that is, prior knowledge). All transcript levels are shown on a log10 scale ranging from 0.1- to 10-fold induction. (A) Invariant genes (blue) compared with all other selected genes (red). (B) Metallothionein genes. (C) Heat shock protein genes. (D) Genes involved in glutathione metabolism. (E) Genes involved in DNA repair mechanisms. (F) Regulators of apoptosis.