Illustration from Scientific Research

Schematic of mouse preimplantation development. Totipotency is restricted to early-stage development (that is, zygote and two-cell stages). Blastomeres gradually transition to a pluripotent state from the four-cell stage onward and develop into a blastocyst consisting of inner cell mass (ICM) and trophectoderm (TE) before implantation in the uterus at 4.5-days postcoitum (dpc).

DOI