Conservation of regulation and function between D. discoideum and D. purpureum transcriptional profiles. We compared the similarity between the transcriptional profiles of orthologs from the two species. (a) The three-dimensional density plot represents the distribution of expression levels (x-axis, average read count) and of the similarities between the transcription profiles of the orthologs (y-axis, Pearson's correlation). The z-axis (gene count) represents the number of genes in each bin (defined by the black gridlines). The histogram behind the density plot summarizes the gene counts in four sections (separated by the yellow lines). The number of genes (top) and their fraction of the total (%) are indicated. (b) The bars represent the number of transcripts with various highly conserved expression patterns (gene counts indicated inside bars). (c) Prominent Gene Ontology terms enriched within each group. (d) Representative expression patterns in D. discoideum (yellow) and D. purpureum (purple). The time (hours; x-axis), relative mRNA abundance (y-axis), and gene names are indicated.