A new perspective of the key moments of embryonic development

Alfonso Martínez Arias, head of the Stembryo Engineering Lab at UPF, participates in a review published in Science in which the authors offer offer a new perspective of the role of a structure in embryonic development known as the primitive streak. In a review published in the journal Science , the researchers Guojun Sheng (Kumamoto University, Japan), Alfonso Martínez Arias (UPF) and Ann Sutherland (University of Virginia Health System, USA) offer a new perspective of the role of a structure in embryonic development known as the primitive streak. The primitive streak was established as the first sign of the human being during development and therefore current regulations in many countries do not allow embryos to be grown beyond its appearance, 14 days after fertilization. In the present study, the scientists perform a synthesis of what is known about this structure including recent studies on models of embryonic processes based on stem cells. The authors conclude that the primitive streak is not necessary for the organization of the embryo. They suggest, therefore, that the choice of the appearance of this structure as the first indication of the human being, the -14-day rule-, is arbitrary. Recently, technical advances have recommended a review of this rule to allow experimenting with embryos beyond day 14; this work provides scientific arguments to support such a change.