Supplementary Figure 9: Correlative image analysis and the mining of KEGG database identified the molecular signaling pathways in the morphogenetic domains ( the most posterior position). We identified 20 distinct gene expression patterns by graphics image clustering analysis (clusters shown in the order of left-to-right, top-to-bottom). (A) In the most posterior position, along the A-P axis, we detected PI3K/Akt pathway, a member of phosphatidylinositol signaling system, in cluster 20 (neuron) but not cluster 4 and 12 (hypodermis-and-neuron). During neuron development, PI3K-Akt is critical in mediating neuronal protrusion [36], and synaptic polarity [37]. (B) In the most posterior position, along the V-D axis, we identified the ‘ECM receptor interaction’ pathway that was specifically expressed in cluster 13 (muscle), but not other clusters. Recently, it was reported that muscle functions as a connective tissue and source of extracellular matrix in planarians, the flatworms [38]. It is to be clarified if such Biology Process is evolutionarily conserved between the two types of worms and active in regulating C. elegans embryogenesis. (C) In the most posterior position, along the L-R axis, the Jak-STAT signaling pathway was detected in cluster 1 (neuron) but not cluster 7 and 20 (posterior neuron-hypodermis domains). It plays critical roles in regulating the proliferation and differentiation of neural progenitor cells (NPCs), and astrocytic differentiation after spinal cord injuries [39].