Moving group analyses of individual ancestor indexes obtained during embryogenesis. A–E: moving group analysis of the ancestor indexes within all genes (25,613 genes). Grouped stage number represents the earlier stage of a pair of developmental stages (e.g. gene expression of grouped stage 14 represents non-redundant genes expressed at stage 14 or 15; see Table 1 for staging). Each stage contained on average 22,744 EST counts (4,418–44,210), which corresponded to on average 4,396 (1,493–6,507) non-redundant ENSEMBL M. musculus genes. F–G: Moving group analysis of the ancestor indexes within developmental genes. Each stage contained on average 1,479 EST counts (282–3,406), which corresponded to 303 (94–491) non-redundant ENSEMBL M. musculus genes. E, M and L indicate the early, middle and late embryonic periods, covering non-redundant genes expressed in stages 2–7, 11–18 and 25–31, respectively. Statistical analysis was performed with Fisher's exact test. Significant differences are indicated by asterisks. n.s: P > 0.05. Within each graph, relative areas of circles reflect the number of expressed (total or developmental) genes at each stage.