Extended Data Fig. 2: Expression profiling of transcription factors across ontogenetic stages.

(a) Distribution of gene expression levels for transcription factors (TFs) (orange) and all genes (blue) across different ontogenetic stages. In all samples, TF genes have higher average expression than all genes. The black lines inside the box indicate the median values, and the whiskers extend from the first or third quartiles to the minimum or maximum values. (b) Numbers of TFs expressed in each sample (blue bars) and the proportion of expressed TFs versus all expressed genes, given as a percentage (red points). The numbers of expressed TFs vary in different samples, ranging from 331 in the 2-8cell stage to 577 in the juvenile scallop. In all samples, TFs constitute ~4% of all expressed genes. (c) The expression of ubiquitous TFs spans almost six orders of magnitude while the expression of stage-restricted expressed TFs was usually high but restricted in certain ontogenetic stages. For each ontogenetic stage, gene names are shown for the top five TFs with the largest fold change relative to the average expression level of all other stages. The ubiquitous and restricted TFs are indicated in blue and red, respectively.