Dissecting primate early post-implantation development using long-term in vitro embryo culture

In vitro development of monkey embryos Owing to technical and ethical limitations, the molecular and cellular mechanisms underlying primate gastrulation are far from clear (see the Perspective by Tam). Two independent studies used an in vitro culture system to study cynomolgus monkey embryo postimplantation development up to and beyond gastrulation (day 9 to day 20). Niu et al. observed in vivo morphogenetic events and used single-cell RNA sequencing and single-cell chromatin accessibility to study the distinct cell lineages in developing embryos. Ma et al. also observed that key events of in vivo early development were recapitulated in their system, and single-cell RNA-sequencing analysis revealed molecular signatures of postimplantation cell types. These systems will help elucidate the dynamics and regulation of gastrulation in primates, including possible relevance to human development. Science , this issue p. eaaw5754 , p. eaax7890 ; see also p. 798