The British embryologist Lewis Wolpert (1929-2021) left a legendary phrase: “The most important moment of your life is not your birth, nor your marriage, nor your death, but gastrulation.” Exactly, 14 days after a sperm and an egg come together, the embryo, a tiny sphere of a few hundred cells, will begin gastrulation, a week-long process in which that little ball will become the first sketch of the individual. Those days are the greatest enigma of the formation of a human being, because of the technical and ethical barriers to investigating them. The Palestinian scientist Jacob Hanna, one of the world leaders in this field, has managed to create a new human embryo model, obtained from stem cells, that imitates the three-dimensional architecture of a natural embryo between 7 and 14 days, according to its preliminary results, at which that EL PAÍS has had access to. “It is the first time that synthetic human embryos have been obtained without genetic modifications,” says Hanna, from the Weizmann Institute of Sciences, in Rehovot (Israel). The draft of their study has since been published in the bioRxiv repository.
