Motoo Kimura

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Motoo Kimura

Foreign Member of the Royal Society[1]
Scientific career
Fields
InstitutionsNational Institute of Genetics
ThesisStochastic Processes in Population Genetics (1956)
Doctoral advisorJames F. Crow
Other academic advisors

Motoo Kimura (木村 資生, Kimura Motō) (November 13, 1924 – November 13, 1994) was a Japanese biologist best known for introducing the neutral theory of molecular evolution in 1968.[2][3] He became one of the most influential theoretical population geneticists. He is remembered in genetics for his innovative use of diffusion equations to calculate the probability of fixation of beneficial, deleterious, or neutral alleles.[4] Combining theoretical population genetics with molecular evolution data, he also developed the neutral theory of molecular evolution in which genetic drift is the main force changing allele frequencies.[5] James F. Crow, himself a renowned population geneticist, considered Kimura to be one of the two greatest evolutionary geneticists, along with Gustave Malécot, after the great trio of the modern synthesis, Ronald Fisher, J. B. S. Haldane, and Sewall Wright.[6]

Life and work

Kimura was born on November 13, 1924, in

biometry.[1]

Due to

Kyoto Imperial University in 1944. On the advice of the prominent geneticist Hitoshi Kihara, Kimura entered the botany program rather than cytology because the former, in the Faculty of Science rather than Agriculture, allowed him to avoid military duty. He joined Kihara's laboratory after the war, where he studied the introduction of foreign chromosomes into plants and learned the foundations of population genetics.[7][1]

In 1949, Kimura joined the

Kimura soon found Iowa State College too restricting; he moved to the University of Wisconsin to work on stochastic models with

His accomplishments at Wisconsin included a general model for genetic drift, which could accommodate multiple alleles, selection, migration, and mutations, as well as some work based on

Kolmogorov backward equation to population genetics, allowing the calculation of the probability of an allele to become fixed in a population.[8] He received his PhD in 1956, before returning to Japan (where he would remain for the rest of his life, at the National Institute of Genetics).[1]

Kimura worked on a wide spectrum of theoretical population genetics problems, many of them in collaboration with

genetic sequences. The stepwise mutation model is a "ladder model" that can be applied to electrophoresis studies where homologous proteins differ by whole units of charge. An early statement of his approach was published in 1960, in his An Introduction to Population Genetics.[10] He also contributed an important review article on the ongoing controversy over genetic load in 1961.[1][11]

1968 marked a turning point in Kimura's career. In that year he introduced the neutral theory of molecular evolution, the idea that, at the molecular level, the large majority of genetic change is neutral with respect to natural selection—making genetic drift a primary factor in evolution.[12][13] The field of molecular biology was expanding rapidly, and there was growing tension between advocates of the expanding reductionist field and scientists in organismal biology, the traditional domain of evolution. The neutral theory was immediately controversial, receiving support from many molecular biologists and attracting opposition from many evolutionary biologists.[14][12]

Kimura spent the rest of his life developing and defending the neutral theory. As James Crow put it, "much of Kimura's early work turned out to be

pre-adapted for use in the quantitative study of neutral evolution".[1] As new experimental techniques and genetic knowledge became available, Kimura expanded the scope of the neutral theory and created mathematical methods for testing it against the available evidence.[14] Kimura produced a monograph on the neutral theory in 1983, The Neutral Theory of Molecular Evolution, and also worked to promote the theory through popular writings such as My Views on Evolution, a book that became a best-seller in Japan.[15]

Though difficult to test against alternative selection-centered hypotheses, the neutral theory has become part of modern approaches to molecular evolution.[16][17]

In 1992, Kimura received the

Foreign Member of the Royal Society.[1]

Kimura suffered from progressive weakening caused by

amyotrophic lateral sclerosis later in life.[6] In an accidental fall at his home in Shizuoka, Japan, Kimura struck his head and died on November 13, 1994, of a cerebral hemorrhage.[7][18][6] He was married to Hiroko Kimura. They had one child, a son, Akio, and a granddaughter, Hanako.[19][20]

Honors

See also

References

  1. ^
    S2CID 44725944
    .
  2. .
  3. .
  4. .
  5. .
  6. ^ .
  7. ^ . Retrieved 27 February 2023.
  8. .
  9. .
  10. ^ Kimura Motoo, Shūdan Idengaku gairon, Baifūkan, Tokyo 1960
  11. ^ Kimura, M (1961). "Some calculations on the mutation load". Jpn. J. Genet. 36: 179–190.
  12. ^
    ISSN 0066-4162
    . Retrieved 28 February 2023.
  13. .
  14. ^ . Retrieved 28 February 2023.
  15. ^ Kimura, Motoo (1988). Seibutsu shinka wo kangaeru (My views on evolution) (in Japanese). Iwanami Shoten.
  16. ^ Nei, Masatoshi (1987). Molecular Evolutionary Genetics. Columbia University Press.
  17. PMID 8813018
    .
  18. ^ "Motoo Kimura; Japanese Geneticist, 70". The New York Times. November 16, 1994.
  19. S2CID 29545568
    .
  20. ^ Brenner's Encyclopedia of Genetics, 2nd Edition[1]
  21. ^ "John J. Carty Award for the Advancement of Science". National Academy of Sciences. Archived from the original on 29 December 2010. Retrieved 25 February 2011.
  22. ^ Royal Society: archived record