Hilde Proescholdt Mangold Biography

German biologist Hilde Mangold studied the process by which part of an embryo--sometimes called an organizer--causes other parts of the embryo to form specific types of tissues and organs. This process is called embryonic induction. Working under the direction of German biologist Hans Spemann (1869-1941), Mangold helped discover the location of the organizer in amphibians.

Mangold had attended the University of Frankfurt, where she had once been to a lecture by Hans Spemann. Spemann was studying the processes that control the development of amphibian embryos, and Mangold was intrigued by his experiments. After she graduated, she moved to Freiburg, Germany, where Spemann was head of the Zoological Institute. Mangold began working on an advanced degree, and Spemann suggested a series of experiments for her doctoral thesis.

Spemann proposed that Mangold should work with early embryos of two species of newts. Her experiments would involve transplanting a portion of one embryo to a different part of an embryo of the other species. Because one newt species had light cells, and one had dark cells, she would be able to determine exactly what happened to the transplant as the embryo developed.

Earlier experiments (using a single species of newt) had shown that the fate of most transplanted cells was determined by the recipient embryo rather than by the donor. For instance, if cells that would normally become belly skin were transplanted to an area that would normally become back skin, the transplanted cells would become back skin. This result indicated that the fate of the cells was not yet determined when they were transplanted.

This was not the case for one region of the early embryo--the region that would eventually form the neural tube. (The neural tube, in turn, eventually forms the newt's brain and spinal cord.) When these cells were transplanted, they continued to form a neural tube regardless of their location. In other words, the fate of these cells was already determined in the early embryo.

It was these cells that would eventually form a neural tube, that Mangold transferred between the two species. To her and Spemann's surprise, Mangold found that in such a transplant, most of the cells making up the resulting neural tube came from the recipient of the transplant rather than the donor. Therefore, the transplant cells were somehow able to control not only their own fate, but also the fate of the cells surrounding them. They induced these cells to develop into tissues and organs that they would not normally form. In fact, not only would a second spinal cord and brain be produced, but other internal organs as well. The eventual result was a secondary embryo attached to the main embryo (similar to a conjoined twin).

Spemann named this transplanted region the organizer because it was capable of reorganizing the cells in the recipient embryo. Mangold and Spemann wrote a paper on their results. (The paper was also Mangold's thesis for her doctorate degree.) Just as the paper was being published, Mangold was killed (at the age of 26) when a heater in her kitchen exploded. Spemann, however, went on to win a Nobel Prize in 1935 for the discovery of the organizer. (Mangold's death made her ineligible.) This Nobel Prize was one of the few that have ever been awarded for work based on a doctoral thesis,in this case, the thesis of Hilde Mangold.