fig2
From: Advances in early human embryonic development and organogenesis from spatiotemporal multi-omics
Figure 2. E14 serves as a widely recognized ethical boundary for in vitro embryo culture in many jurisdictions, aligning with the onset of gastrulation. E14-E21 represents the gastrulation period; E21-E28 represents the early organogenesis period. Together, E14-E28 constitutes the "black box" period of early human development, for which our current understanding remains limited. TE: Trophectoderm; ICM: inner cell mass; EPI: epiblast; HYPO: hypoblast; AM: amnion; YS: yolk sac; CS: connecting stalk; PS: primitive streak; PL: placenta.
