Intestinal motility is an important stage in the embryonic development of most animals, and is one of the hotspots and focuses of life science research. Researchers from the Institute of Zoology of the Chinese Academy of Sciences, the Beijing Institute of Stem Cell and Regenerative Medicine, and the China Agricultural University reconstructed the first complete human gastrula model with digital 3D for the first time, which greatly promoted human cognition of how life began to develop. This achievement was published in the international academic journal Cell on April 23. In life sciences, the first eight weeks of human embryonic development are divided into 23 Carnegie stages (CS1-CS23), and the primary stage of intestinal motility occurs between CS7-CS8, which is between 14 and 21 days after fertilization. At this stage, the blastocyst with only one layer of cells undergoes recombination, forming a structure consisting of three embryonic layers (i.e. ectoderm, mesoderm, and endoderm), and the newly formed three embryonic layer cells combine and coordinate to develop into various organs. Each embryonic cell can develop into specific organs and tissues. However, according to the ethical norms of life science research, the in vitro cultivation of human embryos is limited to 14 days. Therefore, although people have adopted methods such as constructing embryos using pluripotent stem cells in vitro to study intestinal motility, they have never been able to prepare to understand its process, and intestinal motility is also considered a "black box" of human development. Researcher Yu Leqian from the Institute of Zoology of the Chinese Academy of Sciences and the Beijing Institute of Stem Cell and Regenerative Medicine, the main author of the achievement, said: "Based on a complete human embryo in the CS8 period, we used continuous cross-sectional high-resolution space transcriptome slices, combined with machine learning algorithms, to conduct three-dimensional alignment, build a three-dimensional spatial distribution point cloud map of different cell types and gene expression in the complete embryo, and then digitally reconstruct the first complete human gastrula model." This allows researchers to accurately see the relative distribution position of each cell in the embryo. "Combining spatial location information with cell group information and gene expression information allows us to more accurately define different cell types and analyze their interaction with surrounding cells. Taking the formation of mesoderm cells as an example, the migration process of mesoderm is not clear at present. But now, we find that it is very likely that the mesoderm has undergone cell fate determination when it has not migrated out of the original strip, differentiating into axial mesoderm, paraxial mesoderm, intermediate mesoderm and lateral mesoderm lineages, and migrating to the corresponding location according to the determined fate." The article is mainly completed by one of the authors, Institute of Zoology, Chinese Academy of Sciences, and Beijing Stem Cell and Regenerative Medicine Researcher Guo Jingtao of the Research Institute said, It can be said that this work fills the knowledge gap in the development of various cell lineages in human embryos during the gastrulation stage. In addition, the spatial location information of 3D reconstruction allows researchers to explore another important event in the process of gastrulation, namely the formation of the body axis. The body of mammals has three body axes: the head tail axis, the back abdomen axis, and the left right axis, along which various tissues and organs are arranged in order. During embryonic development, vertebrates mainly rely on a type of cell called the tissue center, which gradually establishes the three body axes of the body. In our research, we focused on seven developmental processes of heavy metals