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Thomas Hunt Morgan

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Thomas Hunt Morgan

Thomas Hunt Morgan
Johns Hopkins yearbook of 1891
Born (1866-09-25)September 25, 1866
Lexington, Kentucky
Died December 4, 1945(1945-12-04) (aged 79)
Pasadena, California
Nationality United States
Fields Geneticist
Embryologist
Institutions Bryn Mawr College
Columbia University
California Institute of Technology
Alma mater University of Kentucky (B.S.),
Johns Hopkins University (Ph.D.)
Doctoral students Nettie Maria Stevens
John Howard Northrop
Hermann Joseph Muller
Calvin Bridges
Alfred Sturtevant
Known for Drosophila melanogaster
Linked genes
Notable awards Nobel Prize in Physiology
or Medicine
(1933)
Copley Medal (1939)
Signature

Thomas Hunt Morgan (September 25, 1866 – December 4, 1945)[1] was an American [2]

Morgan received his PhD from genes are carried on chromosomes and are the mechanical basis of heredity. These discoveries formed the basis of the modern science of genetics.

During his distinguished career, Morgan wrote California Institute of Technology has produced seven Nobel Prize winners.

Contents

  • Early life 1
  • Academic career 2
    • Bryn Mawr 2.1
    • Marriage and family 2.2
    • Columbia University 2.3
    • Caltech 2.4
  • Morgan and Evolution 3
  • Legacy and honors 4
  • See also 5
  • References 6
  • Further reading 7
  • External links 8

Early life

Morgan was born in John Wesley Hunt had 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, governor and senator from Maryland.[3] Following the Civil War, the family had fallen on harder times with the temporary loss of civil and some property rights for those who aided the Confederacy. His father 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 zoology at the recently founded Johns Hopkins University, the first research-oriented American university. After two years of experimental work with morphologist William Keith Brooks and writing 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. The College offered Morgan a full professorship; however, he chose to stay at Johns Hopkins and was awarded a relatively large fellowship to help him fund his studies.

Under Brooks, Morgan completed his thesis work on the embryology of Ph.D. from Johns Hopkins in 1890, and was also awarded the Bruce Fellowship in Research. He used the fellowship to travel to Jamaica, the Bahamas and to Europe to conduct further research.[5]

Nearly every summer from 1890 to 1942, Morgan returned to the Marine Biological Laboratory to conduct research. He became very involved in governance of the institution, including serving as an MBL trustee from 1897 to 1945.[6]

Academic career

Bryn Mawr

In 1890, Morgan was appointed associate professor (and head of the biology department) at Johns Hopkins' sister school sea acorns, ascidian worms and frogs.

In 1894 Morgan was granted a year's absence to conduct research in the laboratories of Science Following

Sex linked inheritance of the white eyed mutation.

In 1900 three scientists, mutation theory with his experimental heredity work. He was initially 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.

[15] Extensive work in

When Morgan took the professorship in experimental zoology, he became increasingly focused on the mechanisms of heredity and evolution. He had published Evolution and Adaptation (1903); like many biologists at the time, he saw evidence for biological evolution (as in the common descent of similar species) but rejected Darwin's proposed mechanism of natural selection acting on small, constantly produced variations.

In a typical Drosophila genetics experiment, male and female flies with known phenotypes are put in a jar to mate; females must be virgins. Eggs are laid in porridge which the larva feed on; when the life cycle is complete, the progeny are scored for inheritance of the trait of interest.

Later in 1904, E. B. Wilson—still blazing the path for his younger friend—invited Morgan to join him at Columbia University. This move freed him to focus fully on experimental work.[14]

Columbia University

On June 4, 1904, Morgan married virologist at Johns Hopkins, specializing in polio research.

Marriage and family

When Morgan returned to Bryn Mawr in 1895, he was promoted to full professor. Morgan's main lines of experimental work involved sex determination, which he had previously dismissed when Nettie Stevens discovered the impact of the Y chromosome on sex. He also continued to study the evolutionary problems that had been the focus of his earliest work.[13]

At the time, there was considerable scientific debate over the question of how an embryo developed. Following sea urchin eggs could be induced to divide without fertilization by adding magnesium chloride. Loeb continued this work and became well known for creating fatherless frogs using the method.[11] [12]

[9] 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's illustration of crossing over, from his 1916 A Critique of the Theory of Evolution

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 Alfred Sturtevant developed the first genetic map in 1913.

In 1915 Morgan, Sturtevant,

In the following years, most biologists came to accept the Richard Goldschmidt and others thought there was no compelling reason to view genes as discrete units residing on chromosomes.[18]

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,

  • Nobel Prize Biography
  • Thomas Hunt Morgan Biological Sciences Building at University of Kentucky
  • Thomas Hunt Morgan
  • Thomas Hunt Morgan — Biographical Memoirs of the National Academy of Sciences

External links

  • Allen, Garland E. (1978). Thomas Hunt Morgan: The Man and His Science.  
  • Allen, Garland E. (2000). "Morgan, Thomas Hunt".  
  • Kohler, Robert E. (1994). Lords of the Fly: Drosophila Genetics and the Experimental Life.  
  • Shine, Ian B; Sylvia Wrobel (1976). Thomas Hunt Morgan: Pioneer of Genetics.  
  • Stephenson, Wendell H. (April 1946). "Thomas Hunt Morgan: Kentucky's Gift to Biological Science". Filson Club Historical Quarterly 20 (2). Retrieved 2012-02-22. 
  •  

Further reading

  1. ^ a b  
  2. ^ a b "The Nobel Prize in Physiology or Medicine 1933". Nobel Web AB. Retrieved 2010-09-14. 
  3. ^ a b Sturtevant (1959), p283.
  4. ^ Allen (1978), pp11-14, 24.
  5. ^ Allen, Thomas Hunt Morgan: The Man and His Science, pp 46-51
  6. ^ Kenney, D. E.; Borisy, G. G. (2009). "Thomas Hunt Morgan at the Marine Biological Laboratory: Naturalist and Experimentalist".  
  7. ^ Morgan, T. H. (1940). " 
  8. ^ Allen, Thomas Hunt Morgan, pp 50-53
  9. ^ Allen, Thomas Hunt Morgan, pp 55-59, 72-80
  10. ^ Allen, Thomas Hunt Morgan, pp 55-59, 80-82
  11. ^  
  12. ^ Loeb, Jacques (1913). Artificial parthenogenesis and fertilization. University of Chicago Press. 
  13. ^ Allen, Thomas Hunt Morgan, pp 84-96
  14. ^ Allen, Thomas Hunt Morgan, pp 68-70
  15. ^ Allen, Thomas Hunt Morgan: The Man and His Science, pp 105-116
  16. ^ Kohler, Lords of the Fly, pp 37-43
  17. ^ Morgan, Thomas Hunt; Alfred H. Sturtevant, H. J. Muller and C. B. Bridges (1915). The Mechanism of Mendelian Heredity. New York: Henry Holt. 
  18. ^ Allen, Thomas Hunt Morgan, pp 208-213, 257-278. Quotation from p 213.
  19. ^ Kohler, Lords of the Fly, chapter 5
  20. ^ Allen, Thomas Hunt Morgan, pp 214-215, 285
  21. ^ Allen, Thomas Hunt Morgan, pp 227-234
  22. ^ Allen, Garland E. (2009). Ruse, Michael; Travis, Joseph, eds. Evolution. The First Four Billion Years. Harvard University Press. p. 746.  
  23. ^ "I think we shall be justified in rejecting it as an explanation of the secondary sexual differences amongst animals", page 220-221, chapter VI, Evolution and Adaptation, 1903.
  24. ^ Chapter VII of Evolution and Adpatation, 1903.
  25. ^ Bowler, Peter (2003). Evolution. The History of an Idea. University of California Press. chapter 7. 
  26. ^ A Critique of the Theory of Evolution, Princeton University Press, 1916, p. 193-194)
  27. ^ A Critique of the Theory of Evolution, page 189.
  28. ^ Kandel, Eric. 1999. "Genes, Chromosomes, and the Origins of Modern Biology", Columbia Magazine

References

  • List of books by Thomas Hunt Morgan
  • History of genetics
  • History of model organisms
  • Centimorgan - unit of genetic crossover

See also

  • Johns 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.
  • The Thomas Hunt Morgan School of Biological Sciences at the University of Kentucky is named for him.
  • The Thomas Hunt Morgan Medal, named in his honor, to 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.
  • A junior high school in Shoreline, Washington was named in Morgan's honor for the latter half of the 20th century.

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 [28]

Legacy and honors

Morgan was interested in evolution throughout his life. He wrote his thesis on the phylogeny of sea spiders ([26] Injurious mutations have practically no chance of becoming established.[27] Far from rejecting evolution, as the title of his 1916 book may suggest, Morgan laid the foundation of the science of genetics. He also laid the theoretical foundation for the mechanism of evolution: natural selection. Heredity was a central plank of neo-Darwinian synthesis, despite his criticism of Darwin at the beginning of his career. Much work on the Evolutionary Synthesis remained to be done.

Morgan and Evolution

Morgan had throughout his life suffered with a chronic duodenal ulcer. In 1945, at age 79, he experienced a severe heart attack and died from a ruptured artery.

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.

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 genetic counselling. In 1939 he was awarded the Copley Medal by the Royal Society.

Morgan moved to California to head the Division of Biology at the Boris Ephrussi, Edward L. Tatum, Linus Pauling, Frits Went, and Sidney W. Fox.

Caltech

Morgan's 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 Hale to establish a school of biology in California.

[21] and worse.racism movement. This adopted the ideas of genetics in support of eugenics After 1915, he also became a strong critic of the growing [20]

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