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An important scientist in the history of cloning, Hans Spemann is considered one of the pioneers of cloning technology. The German embryologist (27 June 1869– 9 September 1941) was renowned for his work in experimental embryology and for his mastery of and development of micro-surgery techniques. In 1935, he won the Nobel Prize in Physiology or Medicine for his discovery of Organizer Effect in Embryonic Induction.
What Spemann discovered was that when certain areas in an embryo were transplanted to another part of a different embryo, the former influenced the new adjacent cells and induced them to develop in a manner not usual to those cells; for example, those cells could give rise to organs and tissues that wouldn't have normally developed in that area. Spemann called the influence-inducing parts 'Organizers' or 'Differentiation or Organizing Centers', and the process 'Embryonic Induction'.
This famous scientist found that –
- Different embryo parts resulted from different parts of an organization center. For example, the head developed from the anterior part and the tail from the posterior part.
- In cell development, the relative position of the cells to a differentiation center mattered more than cell ancestry. The developmental fate of cells changed when this relative position changed. Tail organizers, for instance, didn't develop tail parts when grafted into the head region – they obeyed the head organizer and gave rise to head parts.
- In older embryos, however, some parts already had a specified destiny. The process of determination, where the future function of each part was determined, took place at some point in the development from the early stage embryo.
This was a major step forward in the field of embryology. Spemann's conclusion that there were no foreordained organs and tissues in an early-stage embryo – these developed as the embryo evolved - swung the balance towards epigenesis in the then-raging preformation vs. epigenesis debate.
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Early Life, Education and Scientific Career
The eldest of Wilhem and Lisinka Spemann's four children, Hans Spemann grew up in an intellectual atmosphere. His father, a respected Stuttgart-based publisher, was well-to-do and the family had a high social standing. Their large house included a good-sized library which was open to the children and the young Hans Spemann, in particular, appears to have been a voracious reader. Though his later life was devoted to science, he always remained deeply interested in art, literature and philosophy.
After studying the classics at the Eberhard-Ludwig School in Stuttgart from 1878 until 1888, Spemann joined his father's publishing business. A call-up for compulsory military service interrupted this career and he spent the period between 1889-1890 serving with the Kassel Hussars. After his discharge, he headed to Hamburg to work as a retail book-seller.
However, his interest in science proved stronger than the familial leaning towards publishing and book-selling and he enrolled at the University of Heidelberg to study medicine in 1891. This proved propitious for his future career as he studied under people like the zoologist Otto Butschli and the anatomist Karl Gegenbaur. He also met the biologist Gustav Wolff and became fascinated with his experiments on newt embryos, which had highlighted the regeneration capabilities of developing newt eye lens.
In 1893, Spemann took his preliminary examination and, in the winter of 1893-1894, entered the University of Munich for his Fifth Semester, which was clinical training in medicine. The high point of his Munich sojourn was probably becoming acquainted with the classical scholar August Pauly. Clinical medicine certainly didn't hold his attention as much as his burgeoning interest in embryology and in the spring of 1894, he shifted base to the University of Wurzburg’s Zoological Department. Here, working under the Director of the Zoological Department, Theodore Boveri, the physicist Wilhelm Rontgen and the botanist Julius von Sachs, further fueled Spemann's scientific interest and development.
Under Boveri’s guidance, Spemann finished his doctoral dissertation in 1894-1895. His PhD thesis concerned cell lineage study in the Strongylus paradoxus parasitic worm. In 1898, for his Habilitation (teaching qualification), he presented a comparative analysis of the embryonic development of the amphibian middle ear.
Joining the faculty as a Privatdozent (assistant lecturer) in Zoology in 1898, Spemann remained at Wurzburg until 1908 when the Zoological Institute in Rostock offered him the post of Professor of Zoology and Comparative Anatomy.
In 1914, along with Carl Correns, he became the Associate Director of the Kaiser Wilhelm Institute of Biology at Dahlem in the outskirts of Berlin.
He succeeded Hans Doflein as Professor of Zoology at the University of Freiburg-im-Breisgau in 1919. He stayed on at Freiburg until his retirement in 1937. His student Otto Mangold then took on his chair.
Four years after his retirement, on 9 September 1941, Hans Spemann died from heart failure at the age of 74. His family included his wife Klara (neé Binder, married in 1892) and their three sons and one daughter.