's theorization of a "fantastic experiment" to
De Robertis, "Frzb-1 is a secreted antagonist of Wnt signaling expressed in the Spemann
organizer," Cell, vol.
's experiments, in 1924, suggested that the dorsal blastopore lip represents a differentiation center from which the determination process gradually expands toward the nondetermined ectoderm, in the gastrula stage .
Harland, "Expression cloning of noggin, a new dorsalizing factor localized to the Spemann
organizer in Xenopus embryos," Cell, vol.
From 1900-1950, other prominent developmental biologists including Driesch, Spemann
, and Weiss worked from this same perspective.
organizer signal noggin binds and inactivates bone morphogenetic protein 4.
(110) In 1901, Hans Spemann
, a German embryologist, successfully "split a 2-cell salamander embryo into two parts, which developed into two complete organisms.
Normally, cortical rotation activates the Nieuwkoop center of the vegetal hemisphere, which will thereafter in the blastula induce the formation of the Spemann
organizer region in the marginal zone.
Meyer begins the narrative in chapter 14 by outlining the experiments of Hans Spemann
and his PhD student Hilda Mangold in the 1920s on developing newts, plus some important subsequent studies during the middle-twentieth century, which demonstrated the significance of the cellular chemical environment for gene expression during development.
Early in the 20th century, German biologist Hans Spemann
separated two cells of a salamander zygote using a strand of his daughter's hair.