In vitro investigation of mammalian early embryonic development

Mammalian embryonic development starts from a fertilized egg, which cleaves to form morula and blastocyst. At the same time, the early embryo is transported from the fallopian tube to the uterus for implantation. After implantation, the embryo undergoes gastrulation and forms a gastrula, further developing a new individual. The development of embryo in the uterus causes the difficulties in sampling and observation, hindering the understanding of mammalian embryonic development. Therefore, it is necessary to develop the technology to overcome the barrier of in vivo embryonic development. In December 2021, "Embryo 'husbandry' opens windows into early development" was selected as one of Science's 2021 breakthroughs. This review focuses on the achievements of in vitro mammalian embryos and discusses their limitations and the future applications for the investigation of mammalian embryonic development and human related diseases.