Reconstructing Mammalian Embryogenesis InVitro Through Lineage Specification, Morphogenetic Self-Organization and Programmable Stem Cell-Based Embryo Models

Stem-cell-based embryo models (SCBEMs) have emerged as powerful experimental systems for investigating how mammalian embryos acquire cellular identity, establish spatial organization and undergo coordinated morphogenesis. This review traces the development of SCBEMs from embryoid bodies and gastruloids to ETS, ETX and ETiX/EiTiX models, highlighting how the progressive incorporation and engineering of embryonic and extraembryonic lineages has improved the reconstruction of early developmental events.