Nodes represent upregulated genes in ES cells in a conserved (blue, upregulated in both hES and mES cells) or species-specific (red, upregulated in mES cells only) manner. Edges represent positive regulatory relationships (activation) that are validated by ChIP-chip and RNAi data in both species (dark blue), in mouse only (red), or in human only (light blue). As the KLF module appears to have lost its regulatory function in hES cells, its target genes ESRRB, FOXD3 and SOCS3 have consistently lost their upregulation in hES cells as well (A). However, LIN28 and NODAL, which are upregulated by the KLF module in mES cells, remain upregulated in hES cells. Their upregulation in hES cells might be activated by NANOG and OCT4 instead (B).