Hans Spemann
Encyclopedia
Hans Spemann was a German
Germans
The Germans are a Germanic ethnic group native to Central Europe. The English term Germans has referred to the German-speaking population of the Holy Roman Empire since the Late Middle Ages....

 embryologist
Embryology
Embryology is a science which is about the development of an embryo from the fertilization of the ovum to the fetus stage...

 who was awarded a Nobel Prize in Physiology or Medicine
Nobel Prize in Physiology or Medicine
The Nobel Prize in Physiology or Medicine administered by the Nobel Foundation, is awarded once a year for outstanding discoveries in the field of life science and medicine. It is one of five Nobel Prizes established in 1895 by Swedish chemist Alfred Nobel, the inventor of dynamite, in his will...

 in 1935 for his discovery of the effect now known as embryonic induction
Embryogenesis
Embryogenesis is the process by which the embryo is formed and develops, until it develops into a fetus.Embryogenesis starts with the fertilization of the ovum by sperm. The fertilized ovum is referred to as a zygote...

, an influence, exercised by various parts of the embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...

, that directs the development of groups of cells into particular tissues and organs.

Biography

Hans Spemann was born in Stuttgart
Stuttgart
Stuttgart is the capital of the state of Baden-Württemberg in southern Germany. The sixth-largest city in Germany, Stuttgart has a population of 600,038 while the metropolitan area has a population of 5.3 million ....

, the eldest son of publisher Wilhelm Spemann and his wife Lisinka, née Hoffman. After he left school in 1888 he spent a year in his father's business, then, in 1889–1890, he did military service in the Kassel Hussars followed by a short time as a bookseller in Hamburg. In 1891 he entered the University of Heidelberg where he studied medicine, taking his preliminary examination in 1893. There he met the biologist and psychologist Gustav Wolff who had begun experiments on the embryological developments of newts and shown that, if the lens of a developing newt's eye is removed, it regenerates.

In 1892 Spemann married Klara Binder: the couple were to have two sons. In 1893–1894 he moved to the University of Munich for clinical training but decided, rather than becoming a clinician, to move to the Zoological Institute at the University of Würzburg, where he remained as a lecturer until 1908. His degree in zoology, botany, and physics, awarded in 1895, followed study under Theodor Boveri
Theodor Boveri
-External links:* Fritz Baltzer. . excerpt from . University of California Press, Berkeley; pp. 85–97....

, Julius Sachs and Wilhelm Röntgen.

For his Ph.D. thesis under Boveri, Spemann studied cell lineage in the parasitic worm Strongylus paradoxus, for his teaching diploma, the development of the middle ear in the frog.

Experiments in Ontogeny

During the winter of 1896, while quarantined in a sanitarium recovering from tuberculosis, Spemann read August Weismann
August Weismann
Friedrich Leopold August Weismann was a German evolutionary biologist. Ernst Mayr ranked him the second most notable evolutionary theorist of the 19th century, after Charles Darwin...

's book The Germ Plasm: A Theory of Heredity. He wrote in his autobiography: "I found here a theory of heredity and development elaborated with uncommon perspicacity to its ultimate consequences.....This stimulated experimental work of my own"

Results in embryology had been contradictory: in 1888 Wilhelm Roux
Wilhelm Roux
Wilhelm Roux was a German zoologist and pioneer of experimental embryology.Roux was born and educated in Jena, Germany where he attended university and studied under Ernst Haeckel. He also attended university in Berlin and Strasbourg and studied under Gustav Schwalbe, Friedrich Daniel von...

, who had introduced the experimental manipulation of the embryo to discover the rules of development, performed a series of experiments in which he inserted a hot needle into one of two blastomeres to kill it. He then observed how the remaining blastomere developed, and found that it became a half embryo. In 1892 Hans Driesch performed similar experiments on sea urchin embryos, but instead of killing one of the two blastomeres he put many embryos in a tube and shook it to separate the cells. He reported that, contrary to Roux's findings, he ended up with completely formed but smaller embryos. The reason for this discrepancy has been widely attributed to Driesch separating the two blastomeres completely rather than just killing one as Roux had done. Others, including Thomas Hunt Morgan
Thomas Hunt Morgan
Thomas Hunt Morgan was an American evolutionary biologist, geneticist and embryologist and science author who won the Nobel Prize in Physiology or Medicine in 1933 for discoveries relating the role the chromosome plays in heredity.Morgan received his PhD from Johns Hopkins University in zoology...

 and Oscar Hertwig, attempted to separate the two cells, for the matter was of great importance, particularly to the arguments between proponents of epigenesis
Epigenesis
Epigenesis may refer to:* Epigenesis , describes morphogenesis and development of an organism* By analogy, a philosophical and theological concept, part of the concept of spiritual evolution* The Epigenesis, a 2010 album by Melechesh...

 and preformation, but satisfactory results could not be achieved.

As a master of micro-surgical technique, beginning with his continuing work on the amphibian eye, Spemann's papers in the early years of the 20th century on this vexed question were to be a great contribution to the development of experimental morphogenesis
Morphogenesis
Morphogenesis , is the biological process that causes an organism to develop its shape...

, causing him to be hailed in some quarters as the true founder of micro-surgery. He succeeded in dividing the cells with a noose of baby hair. Spemann found that one half could indeed form a whole embryo, but observed that the plane of division was crucial. This dispatched the theory of preformation and gave some support to the concept of a morphogenetic field
Morphogenetic field
In developmental biology, a morphogenetic field is a group of cells able to respond to discrete, localized biochemical signals leading to the development of specific morphological structures or organs. The spatial and temporal extent of the embryonic fields are dynamic, and within the field is a...

, a concept of which Spemann learned from Paul Alfred Weiss
Paul Alfred Weiss
Paul Alfred Weiss was an Austrian biologist who specialised in morphogenesis, development, differentiation and neurobiology...

.

Induction and Organisers

Spemann was appointed Professor of Zoology and Comparative Anatomy at Rostock in 1908 and, in 1914, Associate Director of the Kaiser Wilhelm Institute of Biology
Max Planck Institute for Biology
The Max Planck Institute for Biology was located in Tübingen, Germany. It was created as the Kaiser Wilhelm Institute for Biology in Berlin in 1912, and moved to Tübingen 1943. It was one of 80 institutes in the Max Planck Society and was closed in 2005....

 at Dahlem, Berlin. Here he undertook the experiments that would make him famous. Drawing upon the recent work of Warren H. Lewis and Ethel Browne Harvey, he turned his skills to the gastrula, grafting a "field" of cells (the Primitive knot) from one embryo onto another.

The experiments, aided by Hilde Proescholdt (later Mangold)
Hilde Mangold
Hilde Mangold was a German embryologist who was best known for her thesis dissertation performed at the Zoological Institute in Freiburg, Germany under the direction of Hans Spemann...

, a Ph.D. candidate in Spemann's laboratory in Freiburg
Freiburg
Freiburg im Breisgau is a city in Baden-Württemberg, Germany. In the extreme south-west of the country, it straddles the Dreisam river, at the foot of the Schlossberg. Historically, the city has acted as the hub of the Breisgau region on the western edge of the Black Forest in the Upper Rhine Plain...

, took place over several years and were published in full only in 1924. They described an area in the embryo, the portions of which, upon transplantation into a second embryo, organized or "induced" secondary embryonic primordia regardless of location. Spemann called these areas "organiser centres" or "organisers". Later he showed that different parts of the organiser centre produce different parts of the embryo.

Despite his modern reputation, Spemann continued to entertain neo-vitalist "field" analyses similar to those of Driesch, Gurwitsch and Harold Saxton Burr
Harold Saxton Burr
Harold Saxton Burr was E. K. Hunt Professor of Anatomy at Yale University School of Medicine. His early years were spent in Springfield, Massachusetts, while most of his later life was spent in New Haven. In 1908 he was admitted to the Sheffield Scientific School at Yale and received his Ph.B. in...

. However, the follow-up work of Johannes Holtfreter
Johannes Holtfreter
Johannes Holtfreter was a German-born American embryologist. He mixed cells in vitro from embryonic amphibian species and different tissues...

, Dorothy M. Needham
Dorothy M. Needham
Dorothy Mary Moyle Needham FRS was an English biochemist known for her work on the biochemistry of muscle. She was married to biochemist Joseph Needham....

 and Joseph Needham
Joseph Needham
Noel Joseph Terence Montgomery Needham, CH, FRS, FBA , also known as Li Yuese , was a British scientist, historian and sinologist known for his scientific research and writing on the history of Chinese science. He was elected a fellow of the Royal Society in 1941, and as a fellow of the British...

, Conrad Waddington and others showed that organizers killed by boiling, fixing or freezing were also capable of causing induction. The conclusion was that the actual controllers were inert molecules, though little headway was made until the end of the 20th century in discovering how signalling took place.

From 1919 Spemann was Professor of Zoology at the University of Freiburg-im-Breisgau, where he continued his line of enquiry until in 1937 he was relieved of his post to be replaced by one of his first students, Otto Mangold. In 1928 he was the first to perform somatic cell nuclear transfer
Somatic cell nuclear transfer
In genetics and developmental biology, somatic-cell nuclear transfer is a laboratory technique for creating a clonal embryo, using an ovum with a donor nucleus . It can be used in embryonic stem cell research, or, potentially, in regenerative medicine where it is sometimes referred to as...

 using amphibian embryos - one of the first moves towards cloning
Cloning
Cloning in biology is the process of producing similar populations of genetically identical individuals that occurs in nature when organisms such as bacteria, insects or plants reproduce asexually. Cloning in biotechnology refers to processes used to create copies of DNA fragments , cells , or...

. He was awarded the Nobel Prize in 1935. His theory of embryonic induction by organisers is described in his book Embryonic Development and Induction (1938). He died of heart failure on 12 September 1941. He never lost his love of classical literature and, throughout his life, organized evening gatherings of friends to discuss art, literature, and philosophy.

See also

  • Developmental biology
    Developmental biology
    Developmental biology is the study of the process by which organisms grow and develop. Modern developmental biology studies the genetic control of cell growth, differentiation and "morphogenesis", which is the process that gives rise to tissues, organs and anatomy.- Related fields of study...

  • Morphogenesis
    Morphogenesis
    Morphogenesis , is the biological process that causes an organism to develop its shape...

  • Theodor Boveri
    Theodor Boveri
    -External links:* Fritz Baltzer. . excerpt from . University of California Press, Berkeley; pp. 85–97....

  • August Weismann
    August Weismann
    Friedrich Leopold August Weismann was a German evolutionary biologist. Ernst Mayr ranked him the second most notable evolutionary theorist of the 19th century, after Charles Darwin...


External links

  • Explanation of the Spemann-Mangold experiment from a Nature
    Nature (journal)
    Nature, first published on 4 November 1869, is ranked the world's most cited interdisciplinary scientific journal by the Science Edition of the 2010 Journal Citation Reports...

     Reviews article
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