Heat map representation of the observed transcriptomic responses to N-limitation in haploid and diploid Emiliania huxleyi . The color-coding indicates ‘fold-change’ expression values between ≤ −10-fold (red) and ≥10 fold (blue). The density histogram reflects the data distribution, i.e. the frequency of observed expression ratios. In horizontal direction, the heat map depicts the time course of N-limitation in haploid and diploid individuals. In vertical direction, clusters of transcripts reflect the usage of genes, i.e. stage-specific, unidirectional, counter-regulated.