Gene class discovery. A: Clustering of genes, according to their relative gene expression during early embryonic development in Atlantic halibut. Genes were clustered using the single-linkage method with Pearson correlation coefficient as distance measurement. The developmental stages were fertilized eggs (FE); 8-cell stage (8CS), 8 hours past fertilization (hpf); 16 cell stage (16CS), 12 hpf; blastula (BL), 45 hpf; germ ring (GR), 82 hpf; 25% epiboly (25EP) 96 hpf; 50% epiboly (50EP), 117 hpf; and 10 somite stage (10SS), 142 hpf (n = 5). Data was standardized against the first stage, fertilized eggs (FE). Colour bar indicates relative gene expression in relation to FE. Red colour shows up-regulation and blue colour down-regulation in relation to FE. Reference genes are not included. B: Relative gene expressions of selected genes from fertilization to 10 somite stage. Expression pattern of a. Askopos, b. Si:dkey-30j22.9, c. BAH, d. Checkpoint 1, e. Prohibitin 2, f. Synthaxin 4, g. 18 k hypothetical goldfish protein, h. HR6A, i. Tudor 5 protein, j. HHC00057, k. HHC00068, l. HHC00130, m. HHC00222, n. HHC00255, o. HHC00309, p. HHC00334, q. HHC01010, r. HHC01015, s. HHC01032, t. HHC01194, u. HHC01310. Error bars indicate the standard deviation (n = 5).