Figure 4. Correlative image analysis of tissue boundary pattern formation along A-P axis during gastrulation. (A) The gene expression and the morphological pattern computer images generated from the same sections were superimposed for studying the relationship between gene regulation and morphogenesis. The gene expression pattern of pha-4, as an example, showed that at 345 embryonic cell stage, its expression domain was confined to the progenitor populations of pharynx (green color coded) and intestine (cyan color coded). (B) The time course image with central position section indicated that the pha-4 gene was upregulated at detectable level at around 175 cell stage. The spatiotemporal correlative image profile of another example gene, hlh-1, was presented in supplementary Fig. 14.