Embryogenesis is remarkably dynamic & precisely regulated, and the underlying morphogenetic processes are still largely unknown. We aim at understanding the plasticity & robustness of morphogenetic processes in deuterostome early embryogenesis using as a model Siamese zebrafish. Specifically, we expect insights from the quantitative analysis of the: 1) respective contributions of ingression & involution to the formation of the endo-mesodermal layer in endogenous & induced axes; 2) convergence-extension movements in Siamese compared to normal embryos; 3) dynamics of the underlying gene regulatory network. The injection of mRNA encoding a constitutive form of a Nodal pathway receptor (acvr1ba*) into a single blastomere at the 16-cell stage was used to induce a secondary axis. The co-injection of mRNA encoding H2B-mCherry was used to trace the induced axis. Also, we utilized the gsc:egfp transgenic fish line with staining under the control of the goosecoid transcription factor regulatory sequences to reveal the embryonic shields & their derivatives: notochord, prechordal plate & pharyngeal endoderm. Embryos were sorted at shield stage according to the position of the induced shield relative to the endogenous one. According to previous studies, we expected random positioning of the induced shield and an even distribution of embryos across 7 categories, position 0 being at the level of the endogenous shield and 6 being opposite to it. With current categorization of up to 600 embryos, we confirmed this hypothesis. Embryos in opposite positions, class 6, were rare suggesting the requirement for the precise balance of opposing forces, and displayed the most complete duplication of embryonic structures compared to other configurations leading to more or less extensive regulation. Answering the questions above and assessing the balance of biomechanical forces was achieved using cell tracking obtained by the automated analysis of in toto 3D+time imaging. Our best time-lapse data was obtained by 2-Photon microscopy imaging with a horizontal microscope (LaVisionBiotech). We present our most recent results in terms of cell behaviors for class 6 specimens. Our strategy toward the integration of cellular & genetic dynamics relied on the expression of transgenic reporters. Expression of the gsc transgenic reporter in the embryonic shield derivatives revealed unexpected variability with mosaic staining of notochord cells not observed in the endogenous axis. Systematically exploring transgenic reporter expression along the cell lineage is expected to reveal molecular & cellular integrated regulation mechanisms at stake in the robustness of gastrulation morphogenetic processes.