Table 1. Number (%) of the genes with LCP, ICP and HCP promoters.
| Promoter* | 1-cell | 2-cell | 4-cell | Morula | Blastocyst |
| LCP | 171 (8.6)# | 109 (6.0) | 104 (5.7) | 115 (6.4) | 113 (6.2) |
| ICP | 209 (10.5)# | 150 (8.3) | 141 (7.8) | 143 (7.9) | 152 (8.4) |
| HCP | 1610 (80.9) | 1556 (85.7) | 1564 (86.5) | 1549 (85.7) | 1552 (85.4) |
| Total number of genes** | 1990 | 1815 | 1809 | 1807 | 1817 |
* The actively expressed genes ranked in top 2,000 were classified by the CpG contents in their promoters [12]. ** The total numbers of genes was less than 2,000 in each stage and different among the stages because some of the genes were not included in the study of [12] or annotated with RefSeq. # The 1-cell stage is significantly different from all other stages (χ2-test, P < 0.05).