Stochastic processes during mouse blastocyst patterning.

Mammalian preimplantation development serves to form a blastocyst, a structure that is able to implant into the mother's uterus to support further development of the embryo proper. In the developing conceptus, the first differentiation events separate the epithelial trophectoderm from the inner cell mass, which is comprised of the primitive endoderm and embryo-generating epiblast. Although the process of blastocyst formation may appear simple, its morphogenesis and the mechanism(s) of lineage specification are not yet fully understood. Here we discuss findings that suggest the involvement of stochastic processes and the influence of external cues in the patterning process during mouse preimplantation development. (c) 2008 S. Karger AG, Basel.