A pair of research teams unveiled two new ways to replicate a key structure from the earliest days of embryonic development — an advance that could provide important new insight into human development and pregnancy loss, but which also raise thorny questions about research with embryo-like models.
The models described in the two papers, both published Wednesday in the journal Nature, are meant to mimic human blastocysts. Blastocysts are orbs that form about five days after an egg is fertilized. Each contains an outside layer of cells that eventually helps generate the placenta and an internal mass of cells that gives rise to the embryo itself. They’re what implants into the uterus as a pregnancy forms.