Supplementary Figure 4: Method for tomographic imaging of gene expression pattern in virtual reference embryo.(A)-(F) Digital histology sectioning along the three body axes were performed by slicing the embryo body from Anterior to Posterior, Left to Right and Ventral to dorsal side. Linear interpolation and graphics image smoothing with gaussian kernel function was conducted in a rectangular mesh grid to evaluate the gene expression level at each grid point. The red and yellow colors indicated the regions of high gene expression levels of six genes pha-4, hlh-1, cnd-1, end-3, irx-1 and glp-1 selected as the positive controls of the analysis. The results of tomographic imaging were compared and validated by comparing with the corresponding time-lapse video files that were generated in the EPIC database.