- Thomas Hunt Morgan
name = Thomas Hunt Morgan
caption =Johns Hopkins yearbook of 1891
birth_date = Birth date|1866|9|25
death_date = Death date and age|1945|12|4|1866|9|25
field = geneticist embryologist
Johns Hopkins University
John Howard Northrop
Nobel Prize in Physiology or Medicinein 1933
Thomas Hunt Morgan (
September 25, 1866– December 4, 1945) was an American geneticist and embryologist. Morgan received his PhD from Johns Hopkins Universityin 1890 and researched embryology during his tenure at Bryn Mawr. Following the rediscovery of Mendelian inheritancein 1900, Morgan's research moved to the study of mutationin the fruit fly " Drosophila melanogaster". In his famous Fly Room at Columbia UniversityMorgan was able to demonstrate that genes are carried on chromosomes and are the mechanical basis of heredity. These discoveries formed the basis of the modern science of genetics. When he was awarded the Nobel Prize in Physiology or Medicinein 1933 he was the first person awarded the Prize in genetics, "for his discoveries concerning the role played by the chromosome in heredity" [cite web|title=The Nobel Prize in Physiology or Medicine 1933|url=http://nobelprize.org/nobel_prizes/medicine/laureates/1933/index.html] .
During his distinguished career Morgan wrote 22 books [
List of books by Thomas Hunt Morgan] and 370 scientific papers [cite journal|author=Fisher, Ronald A. and G. R. de Beer|date=1947|title=Bibliography of Thomas Hunt Morgan|journal=Obituary Notices of Fellows of the Royal Society|pages=pp. 455–466|url=http://links.jstor.org/sici?sici=1479-571X%28194702%295%3A15%3C451%3ATHM1%3E2.0.CO%3B2-B] , and as a result of his work "Drosophila" became a major model organismin contemporary genetics. The Division of Biology he established at the California Institute of Technologyproduced seven Nobel Prize winners.
Morgan was born in Lexington,
Kentuckyand to Charlton Hunt Morgan and Ellen Key Howard Morgan.Sturtevant (1959), p283.] Part of a long line of Southern aristocracy on his father's side, Morgan was a nephew of Confederate General John Hunt Morganand his great-grandfather John Wesley Hunthad been the first millionaire west of the Allegheny Mountains. Through his mother, he was the great-grandson of Francis Scott Key, the author of the " Star Spangled Banner", and John Eager Howard, a one-time governor and senator from Maryland. However, following the Civil War the family had fallen on harder times with the loss of civil and property rights for those who aided the Confederacy. His father also had difficulty finding work in politics and spent much of his time coordinating veterans reunions.
Beginning at age 16 in the Preparatory Department, Morgan attended the State College of Kentucky (now the
University of Kentucky). There, he focused on science; he particularly enjoyed natural history, and worked with the U.S. Geological Survey in his summers. He graduated as valedictorianin 1886 and was the only studentFact|date=February 2007 to graduate with a bachelor in science. [Allen (1978), pp11-14, 24.] Following a summer at the Marine Biology School in Annisquam, Massachusetts, Morgan began graduate studies in zoologyat the recently founded Johns Hopkins University, the first research-oriented American university. After two years of experimental work with morphologist William Keith Brooksand several publications, Morgan was eligible to receive a master of science from the State College of Kentucky in 1888, the College required two years study at another institution and an examination by the College Faculty.Fact|date=February 2007 The College offered Morgan a full professorship; however, he choose to stay at Johns Hopkins and was awarded a relatively large fellowship to help him fund his studies.Fact|date=February 2007
Under Brooks, Morgan completed his thesis work on the embryology of
sea spiders—collected during the summers of 1889 and 1890 at the Marine Biological Laboratoryin Woods Hole, Massachusetts—to determine their phylogenetic relationship with other arthropods. He concluded that with respect to embryology they were more closely related to spiders than crustaceans. Based on the publication of this work Morgan was awarded his Ph.D. from Johns Hopkins in 1890, and was also awarded the Bruce Fellowship in Research. With the fellowship he was able to travel to Jamaica, the Bahamas and to Europeto conduct further research. [Allen, "Thomas Hunt Morgan: The Man and His Science", pp 46-51]
In 1891, Morgan was appointed associate professor (and head of the biology department) at Johns Hopkins' sister school
Bryn Mawr College, replacing his colleague E. B. Wilson. Morgan taught all morphology-related courses, while the other member of the department, Jacques Loeb, taught the physiological courses; though Loeb only stayed for one year, it was the beginning of a lifelong friendship. [Allen, "Thomas Hunt Morgan: The Man and His Science", pp 50-53] Morgan lectured in biology 5 days a week, giving two lectures a day. He frequently included his own recent research in his lectures, and although he was an enthusiastic teacher, his true interests were in the laboratory. During the first few years at Bryn Mawr he produced descriptive studies of sea acorns, ascidian worms and frogs.
In 1894 Morgan was granted a year's absence to conduct research in the laboratories of
Stazione Zoologicain Naples, where Wilson had worked two years earlier. At the laboratory in Naples he worked with German biologist Hans Driesch, whose research in the experimental study of development piqued Morgan's interest. Among other projects that year, Morgan completed an experimental study of ctenophoreembryology. From his exposure in Naples and through Loeb to the "Entwicklungsmechanik" (roughly, "developmental mechanics") school of experimental biology—a reaction to the vitalistic Naturphilosophiethat was exteremly influential in 19th century morphology—Morgan's work shifted from traditional, largely descriptive morphology to an experimental embryology that sought physical and chemical explanations for organismal development. [Allen, "Thomas Hunt Morgan: The Man and His Science", pp 55-59, 72-80]
At the time there was considerable scientific debate over the question of how an embryo developed. Following
Wilhelm Roux's mosaic theory of development, some believed that hereditary material was divided among embryonic cells, which were then predestined to form particular parts of a mature organism. Driesch and others thought that development was due to epigenetic factors where interactions between the protoplasam and the nucleus of the egg and the environment could affect development. Morgan was in the latter camp; his work with Driesch demonstrated that blastomeresisolated from sea urchinand ctenophore eggs could develop into complete larvae, contrary to the predictions (and experimental evidence) of Roux's supporters. [Allen, "Thomas Hunt Morgan: The Man and His Science", pp 55-59, 80-82] A related debate involved the role of epigeneticand environmental factors in development; on this front Morgan showed that sea urchineggs could be induced to divide without fertilization by adding magnesium chloride, work which was continued by Jacques Loeb (who became well known for creating fatherless frogs using the method). [cite journal
author=Loeb, Jacques|authorlink=Jacques Loeb
journal=American Journal of Physiology | volume=31 | pages=pp 135–138 | date=1899
title=On the Nature of the Process of Fertilization and the Artificial Production of Normal Larvae (Plutei) from the Unfertilized Eggs of the Sea Urchin|url=http://www.stanford.edu/group/Urchin/loeb.htm] [cite book|title=Artificial parthenogenesis and fertilization|author=Loeb, Jacques |publisher=University of Chicago Press | date=1913 | url=http://books.google.com/books?id=6Ct6_1MGe9oC&dq=jacques+loeb+sea+urchin]
Morgan returned to Bryn Mawr in 1895 and was promoted to full professor. Morgan's main lines of experimental work involved regeneration and larval development; in each case, his goal was to distinguish internal and external causes to shed light on the Roux-Driesch debate. He wrote his first book, "The Development of the Frog's Egg", published in 1897. He began a series of studies on different organisms ability to regenerate. He looked at grafting and regeneration in tadpoles, fish and earthworms and in 1901 this work was published as "Regeneration". Beginning in 1900, he started working on the problem of
sex determination; he was also continued to study the evolutionary problems that had been the focus of his earliest work. [Allen, "Thomas Hunt Morgan: The Man and His Science", pp 84-96]
June 4, 1904, Morgan married Lilian Vaughan Sampson (1870-1952), who had entered graduate school in biology at Bryn Mawr the same year Morgan joined the faculty; she put aside her scientific work in the early years of their marriage, but would later contribute significantly to Morgan's "Drosophila" work. Later in 1904, E. B. Wilson—still blazing the path for his younger friend—invited Morgan to join him at Columbia University, which at last freed him to focus fully on experimental work. [Allen, "Thomas Hunt Morgan: The Man and His Science", pp 68-70]
One of their four children (one boy and three girls) was
Isabel Morgan(1911–1996) (marr. Mountain), who became a virologist at Johns Hopkins, specializing in polio research.
By 1904, when Morgan took a professorship in experimental zoology at
Columbia University, he was becoming increasingly focused on the mechanisms of heredity and evolution. The previous year, he had published "Evolution and Adaption"; like many biologists at that time, he saw clear evidence for biological evolution (as in the common descentof similar species) but rejected Darwin's proposed mechanism of natural selectionacting on small, constantly-produced variations. Extensive work in biometryseemed to indicate that continuous natural variation had distinct limits and did not represent heritable changes. Embryological development posed an additional problem in Morgan's view, as selection could not act on the early, incomplete stages of highly complex organs such as the eye. The common solution of the Larmarckian mechanism of inheritance of acquired characters, which featured prominently in Darwin's theory, was increasingly rejected by biologists. According to Morgan biographer Garland Allen, he was also hindered by his views on taxonomy: he thought that species were entirely artificial creations that distorted the continuously variable range of real forms, while he held a "typological" view of larger taxa and could see no way that one such group could transform into another. But while he would remain skeptical of natural selection for many years, his theories of heredity and variation were radically transformed through his conversion to Mendelism. [Allen, "Thomas Hunt Morgan: The Man and His Science", pp 105-116]
In 1900 three scientists,
Carl Correns, Erich von Tschermakand Hugo De Vrieshad rediscovered the work of Gregor Mendel, and with it the foundation of genetics. De Vries had gone on to propose that new species are created by mutation, bypassing the need for either Lamarckism or Darwinism. Morgan dismissed both of these evolutionary theories, and was actually seeking to prove Hugo De Vries' mutation theorywith his experimental heredity work. He was initially quite skeptical of Mendel's laws of heredity (as well as the related chromosomal theory of sex determination), which were being considered as a possible basis for natural selection.
Following C. W. Woodworth and
William E. Castle, around 1908 Morgan started working on the fruit fly " Drosophila melanogaster", and encouraging students to do so as well. With Fernandus Payne, he mutated "Drosophila" through physical, chemical, and radiational means, and began cross-breeding experiments to find heritable mutations. However, they had no significant success for two years. [Kohler, "Lords of the Fly", pp 37-43] Castle had also had difficulty identifying mutations in "Drosophila", hardly unusual given the flies' tiny size. Finally in 1909, a series of heritable mutants appeared, some of which displayed Mendelian inheritance patterns; in 1910 Morgan noticed a white-eyed mutantmale among the red-eyed wild types. When white-eyed flies were bred with a red-eyed female, their progeny were all red-eyed, while a second generation cross produced white-eyed males—a sex-linked recessive trait, the gene for which Morgan named "white". Morgan also discovered a pink-eyed mutant that showed a different pattern of inheritance. In a paper published in "Science" in 1911, he concluded that (1) some traits were sex-linked, (2) the trait was probably carried on one of the sex chromosomes, and (3) other genes were probably carried on specific chromosomes as well.
Morgan and his students became more successful at finding mutant flies; they counted the mutant characteristics of thousands of fruit flies and studied their inheritance. As they accumulated multiple mutants, they combined them to study more complex inheritance patterns. The observation of a miniature wing mutant which was also on the sex chromosome but sometimes sorted independently to the white eye mutation, led Morgan to the idea of
genetic linkageand to hypothesize the phenomenon of crossing over. Morgan proposed that the amount of crossing over between linked genes differs and that crossover frequency might indicate the distance separating genes on the chromosome; later English geneticist J. B. S. Haldanesuggested that the unit of measurement for linkage be called the morgan. Morgan's student Alfred Sturtevantdeveloped the first genetic mapin 1913.
In 1915 Morgan, Sturtevant,
Calvin Bridgesand H. J. Mullerwrote the seminal book "The Mechanism of Mendelian Heredity" [cite book|author=Morgan, Thomas Hunt; Alfred H. Sturtevant, H. J. Muller and C. B. Bridges|title=The Mechanism of Mendelian Heredity|publisher=Henry Holt|location=New York| url=http://books.google.com/books?id=GZEEAAAAYAAJ&dq=mechanism+of+mendelian+heredity+morgan] . Geneticist Curt Sterncalled the book "the fundamental textbook of the new genetics" and C. H. Waddingtonnoted that "Morgan's theory of the chromosome represents a great leap of imagination comparable with Galileo or Newton".Fact|date=February 2007 In the following years, most biologists came to accept the "Mendelian-chromosome theory" pioneered by Morgan and his students. Garland Allen characterized the post-1915 period as one of normal science, in which "The activities of 'geneticists' were aimed at further elucidation of the details and implications of the Mendelian-chromosome theory developed between 1910 and 1915." However, the details of the increasingly complex theory, as well as the very concept of the geneand its physical nature, were still controversial. Critics such as W. E. Castlepointed to contrary results in other organisms suggesting that genes interact with each other, while to Richard Goldschmidtand others, there was no compelling reason to view genes as discrete units residing on chromosomes. [Allen, "Thomas Hunt Morgan: The Man and His Science", pp 208-213, 257-278. Quotation from p 213.]
Because of Morgan's dramatic success with "Drosophila", many other labs throughout the world took up fruit fly genetics. Columbia became the center of an informal exchange network, through which promising mutant "Drosophila" strains were transferred from lab to lab; "Drosophila" became one of the first, and for some time the most widely used,
model organisms. [Kohler, "Lords of the Fly", chapter 5] Morgan's group remained highly productive, but Morgan largely withdrew from doing fly work himself and gave his lab members considerable freedom in designing and carrying out their own experiments. Instead, Morgan returned to embryology and worked to encourage the spread of genetics research to other organisms and the spread of the mechanistic experimental approach ("Enwicklungsmechanik") to all biological fields. [Allen, "Thomas Hunt Morgan: The Man and His Science", pp 214-215, 285] After 1915, he also became a strong critic of the growing eugenicsmovement, which frequently co-opted the ideas of genetics in support of racism and worse. [Allen, "Thomas Hunt Morgan: The Man and His Science", pp 227-234]
John Hopkins awarded Morgan an honorary LL.D. and the University of Kentucky awarded him an honorary Ph.D. He was elected a member of the National Academy of Sciences and made a foreign member of the
Royal Society. In 1924 Morgan received the Darwin Medal. His fly-room at Columbia became world famous and he found it easy to attract funding and visiting academics. In 1927 after 25 years at Columbia, and nearing the age of retirement he received an offer from George Ellery Haleto establish a school of biology in California.
Morgan moved to California to head the Division of Biology at the
California Institute of Technologyin 1928. In establishing the biology division, Morgan wanted to distinguish his program from those offered by Johns Hopkins and Columbia, with research focused on genetics and evolution; experimental embryology; physiology; biophysics and biochemistry. He was also instrumental in the establishment of the Marine Laboratory on Corona del Mar. He wanted to attract the best people to the Division at Caltech, so he took Bridges, Sturtevant, Jack Shultzand Albert Tyler from Columbia and took on Theodosius Dobzhanskyas an international research fellow. More scientists came to work in the Division including George Beadle, Boris Ephrussi, Edward L. Tatum, Linus Pauling, Frits Went, and Sidney W. Fox.
In accordance with his reputation, Morgan held numerous prestigious positions in American science organizations. From 1927 to 1931 Morgan served as the President of the National Academy of Sciences; in 1930 he was the President of the
American Association for the Advancement of Science; and in 1932 he chaired the Sixth International Congress of Genetics in Ithaca, New York. In 1933 Morgan was awarded the Nobel Prize in Physiology or Medicine; he had been nominated in 1919 and 1930 for the same work. As an acknowledgement of the group nature of his discovery he gave his prize money to Bridges', Sturtevant's and his own children. Morgan declined to attend the awards ceremony in 1933, instead attending in 1934. The 1933 rediscovery of the giant polytene chromosomes in the salivary gland of "Drosophila" may have influenced his choice. Until that point, the lab's results had been inferred from phenotypic results, the visible polytene chromosome enabled them to confirm their results on a physical basis. Morgan's Nobel acceptance speech entitled "The Contribution of Genetics to Physiology and Medicine" downplayed the contribution genetics could make to medicine beyond genetic counselling. In 1939 he was awarded the Copley Medalby the Royal Society.
He received two extensions of his contract at Caltech, but eventually retired in 1942, becoming professor and chairman emeritus. George Beadle returned to Caltech to replace Morgan as chairman of the department in 1946. Although he had retired, Morgan kept offices across the road from the Division and continued laboratory work. In his retirement he returned to the questions of sexual differentiation, regeneration, and embryology. Morgan had throughout his life suffered with a chronic
duodenal ulcer, and in 1945 he experienced a severe heart attack and died from a ruptured artery.
Morgan left an important legacy in genetics. Some of Morgan's students from Columbia and Caltech went on to win their own Nobel Prizes, including
George Wells Beadle, Edward B. Lewisand Hermann Joseph Muller. Nobel prize winner Eric Kandelhas written of Morgan, "Much as Darwin's insights into the evolution of animal species first gave coherence to nineteenth-century biology as a descriptive science, Morgan's findings about genes and their location on chromosomes helped transform biology into an experimental science." [Kandel, Eric. 1999. " [http://www.columbia.edu/cu/alumni/Magazine/Legacies/Morgan/ Genes, Chromosomes, and the Origins of Modern Biology] ." "Columbia Magazine"]
The Thomas Hunt Morgan School of Biological Sciences at the University of Kentucky is named for Morgan. In Morgan's honor, the
Genetics Society of Americaannually awards the Thomas Hunt Morgan Medalto one of its members who has made a significant contribution to the science of genetics.
Thomas Hunt Morgan's discovery was illustrated on a 1989 stamp issued in Sweden, showing the discoveries of eight Nobel Prize winning geneticists.
List of books by Thomas Hunt Morgan
History of genetics
History of model organisms
Centimorgan- unit of genetic crossover
*cite book|last=Allen|first=Garland E.|year=1978|title=Thomas Hunt Morgan: The Man and His Science|publisher=
Princeton University Press|isbn=0-691-08200-6
*cite journal|last=Allen|first=Garland E.|year=2000|journal=
American National Biography|publisher= Oxford University Press|title=Morgan, Thomas Hunt
*cite journal|last=Fisher|first=Ronald A.|authorlink=Ronald Fisher|coauthors=G. R. de Beer|year=1947|month=February|journal=Obituary Notices of Fellows of the Royal Society|volume=5|issue=15|title=Thomas Hunt Morgan, 1866-1945|pages=451–466|doi=10.1098/rsbm.1947.0011
*cite book|author=Kohler, Robert E.|year=1994|title=Lords of the Fly: Drosophila Genetics and the Experimental Life|publisher=
University of Chicago Press|isbn=0-226-45063-5
*cite book|last=Shine|first=Ian B|coauthors=Sylvia Wrobel|year=1976|title=Thomas Hunt Morgan: Pioneer of Genetics|publisher=
University Press of Kentucky|isbn=0-8131-0095-X
*cite journal|last=Sturtevant|first=Alfred H.|authorlink=Alfred Sturtevant|year=1959|month=|journal=Biographical Memoirs of the National Academy of Sciences|volume=33|issue=|title=Thomas Hunt Morgan|pages=283–325
* [http://nobelprize.org/medicine/laureates/1933/morgan-bio.html Nobel Prize Biography]
* [http://ukcc.uky.edu/cgi-bin/dynamo?maps.391+campus+0225 Thomas Hunt Morgan Biological Sciences Building at University of Kentucky]
Wikimedia Foundation. 2010.
Look at other dictionaries:
Thomas Hunt Morgan — Nacimiento 25 de septiembre de 1866 Fallecimiento 4 de diciembre de 1945 … Wikipedia Español
Thomas Hunt Morgan — Thomas Hunt Morgan, 1891 Thomas Hunt Morgan (* 25. September 1866 in Lexington, Kentucky; † 5. Dezember 1945 in Pasadena, Kalifornien) war ein US amerikanischer Zoologe und Genetiker, der durch Kreuzungsversuche mit der … Deutsch Wikipedia
Thomas Hunt Morgan — (25 de septiembre de 1866 4 de diciembre de 1945) fue un genético estadounidense. Estudió la historia natural, zoología, y macromutación en la mosca de la fruta Drosophila melanogaster. Sus contribuciones científicas más importantes fueron en el… … Enciclopedia Universal
Thomas Hunt Morgan — Pour les articles homonymes, voir Morgan. Thomas Hunt Morgan Thomas Hunt Morgan Naissance 25 … Wikipédia en Français
Thomas Hunt Morgan — noun United States biologist who formulated the chromosome theory of heredity (1866 1945) • Syn: ↑Morgan • Instance Hypernyms: ↑biologist, ↑life scientist … Useful english dictionary
Thomas Hunt Morgan Medal — The Thomas Hunt Morgan Medal is a medal awarded for lifetime contributions to the field of genetics. The medal is awarded by the Genetics Society of America. Award recipients* 1981 Barbara McClintock and Marcus M. Rhoades * 1982 Sewall Wright *… … Wikipedia
Thomas Hunt Morgan Medal — Die Thomas Hunt Morgan Medal ist eine wissenschaftliche Auszeichnung, die seit 1981 von der Genetics Society of America (GSA) für das Lebenswerk auf dem Gebiet der Genetik vergeben wird. Drei der 33 Preisträger haben später auch einen Nobelpreis… … Deutsch Wikipedia
List of books by Thomas Hunt Morgan — This is a list of books and monographs by the American geneticist Thomas Hunt Morgan. Morgan produced 22 books on embryology, genetics and evolution. Books are in order by date. Three of Morgan s co authors have their own articles: Calvin Bridges … Wikipedia
Medizinnobelpreis 1933: Thomas Hunt Morgan — Der amerikanische Biologe Thomas Hunt Morgan erhielt den Nobelpreis für seine Entdeckungen bezüglich der Rolle der Chromosomen bei der Vererbung. Biografie Thomas Hunt Morgan, * Lexington (Kentucky) 25. 9. 1866, ✝ Pasadena (Kalifornien) 4 … Universal-Lexikon
Thomas H. Morgan — Thomas Hunt Morgan, 1891 Thomas Hunt Morgan (* 25. September 1866 in Lexington, Kentucky; † 5. Dezember 1945 in Pasadena, Kalifornien), war ein US amerikanischer Zoologe und Genetiker, der durch Kreuzungsversuche … Deutsch Wikipedia