Peak expression and correlations throughout development. A. Gene expression profiles ordered by peak expression throughout development. Separate peaks were defined as within the 90% CI of the maximum transcript level measured and at least three stages away from another peak. All genes that changed significantly between any two stages (6,651 of 6,857, 97%) were ordered to gain a broad overview of gene expression throughout development. Most genes (57%) show one peak during development, 30% have two peaks, and 13% have three or more distinct peaks. 4-16 cells encompass stages 4-6. Gastrula encompasses stages 15-18. Heart and circulation encompass stages 25-23. Post-hatch encompasses stages 36-40. B. Correlations of ribosomal genes. Correlation coefficients > 0.4 and < -0.4 are significant at p < 0.01. Red indicates positive correlations and blue indicates negative correlations. The large group of highly positively correlated ribosomal genes has peak expression during pre-mid gastrula. C. Correlations among 1,607 genes significantly differently expressed across all stages (ANOVA, p < 0.01) arranged by peak order. Numbers along the left side and bottom delineate numbers of genes. Correlation coefficients > 0.4 and < -0.4 are significant at p < 0.01. Colors as in 2B.