In vitro culture of cynomolgus monkey embryos beyond gastrulation

Gastrulation is a milestone event of embryonic development, during which germ layers are specified and reassigned into the body plan. Due to the inaccessibility in vivo at this stage and the ethical limitations, gastrulation currently remains a mystery in primates. Here, we report the establishment of an in vitro system to culture cynomolgus monkey embryos after up to 20 days to develop beyond the initiation of gastrulation. The histology, immunostaining and single cell sequencing results showed that the in vitro cultured embryos largely recapitulated the key events of early post-implantation development, and initiated gastrulation in primates. Considering the high similarities between monkeys and humans, this system will provide a unique platform for the investigations of human early post-implantation development at physiological, pathological and environmental conditions. Embryonic mRNAs profile of cynomolgus embryos cultured in vitro for 12, 13, 17 days were generated by single cell RNA sequencing. Day 12, 1 embryo; day 13, 2 embryos; day 17 2 embryos.