Normalized anatomical signature - the anatogram. A linear representation of the CV is used to show the enrichment of annotations within the set of all 3,334 maternally expressed genes versus the entire dataset of 4,759 genes expressed in the embryo. A vertical black line delimits stages, and each colored bar represents an individual CV term (an expanded color key is shown in Additional_data_fille 3). The width of each bar is proportional to the number of times a term was used in our entire dataset, and the height represents the relative enrichment of the given term within the particular gene set (in this case, all maternally expressed genes). Enrichment is given in units of standard deviation above or below the expected sample count based on the background frequencies (z-score). Terms with bars below the zero line are under-represented in the sample. The green asterisk corresponds to the 'amnioserosa' term, while the red asterisk corresponds to the 'brain' term. On the web supplement , the user can place the mouse pointer over any bar in the anatomical signature (arrow on the midgut bar in stage range 13-16) and obtain the gene count for the term in the entire dataset, the gene count within the particular set of genes under study, and a statistical p value of statistical over- or under-representation within the set (shown in the black bordered lavender box).