Tomoko Ohta

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Tomoko Ohta
Tomoko Harada cropped 1 Tomoko Harada 201611.png
Tomoko Ohta
Born (1933-09-07) 7 September 1933 (age 88)
Miyoshi, Japan
Alma materNorth Carolina State University
University of Tokyo
Known forDevelopment of neutral theory of molecular evolution, and nearly neutral theory
AwardsJapan Academy Prize (1985)
Weldon Memorial Prize (1986)
Crafoord Prize (2015)
Scientific career
FieldsEvolutionary biology
InstitutionsNational Institute of Genetics
North Carolina State University
Kihara Institute for Biological Research
Doctoral advisorKen-Ichi Kojima
Other academic advisorsMotoo Kimura
Hitoshi Kihara

Tomoko Ohta (太田 朋子, Ōta Tomoko, born Tomoko Harada 原田 朋子[1] 7 September 1933, Miyoshi, Aichi) is a Japanese scientist working on population genetics/molecular evolution. She and Richard Lewontin were jointly awarded the Crafoord Prize for 2015 "for their pioneering analyses and fundamental contributions to the understanding of genetic polymorphism".


Ohta graduated from the Agriculture Department of the University of Tokyo in 1956. Shortly after graduating, she was hired at the Kihara Institute for Biological Research where she focused on the cytogenetics of wheat and sugar beets. In 1962 an opportunity provided by Hitoshi Kihara to study abroad in the U.S. became available. While a graduate student at the Graduate School of North Carolina State University, she switched her graduate study focus from plant cytogenetics to population genetics. She then was able to assist her advisor, Ken-Ichi Kojima, in working on problems in stochastic population genetics where they took into account the random changes of allele frequencies. She obtained her Ph.D. from North Carolina State University in 1966. Because she had studied abroad as a Fulbright student, she was only able to stay in the United States to finish her Ph.D.

Returning to Japan, Ohta worked under Motoo Kimura, who was the only theoretical population geneticist in Japan at the time.[2] After working on the neutral theory of evolution with her mentor Kimura, she became convinced that nearly neutral mutations (neither deleterious nor entirely neutral) played an important role in evolution.[3] She developed the slightly damaging model (Ohta, 1973), then a more general form, the nearly neutral theory of evolution.[4] She worked at the Japanese National Institute of Genetics from 1969 to 1996,[5] and, in 2002, she was elected to the United States National Academy of Sciences as a foreign associate in evolutionary biology.

She was married to Yasuo Ohta from 1960 to 1972, and has one child.[citation needed]

Reactions to the Nearly Neutral theory[edit]

When Ohta first published her Nearly Neutral theory, she faced difficulty in attracting the scientific research community's attention. Many researchers at the time strongly supported the natural selection theory.[3] Supporting data in protein evolution was sequentially collected in the 1990s, with even more evidence supporting her theory made available throughout the 21st century.[2] There is more and more evidence evolving that supports her nearly neutral theory of evolution. Some examples include: genetic code and the process that occurs during blood clotting.


List of books available in English[edit]

  • Theoretical aspects of population genetics, Motoo Kimura and Tomoko Ohta (1971)
  • Evolution and variation of multigene families, Tomoko Ohta (1980)
  • Population genetics and molecular evolution: papers marking the sixtieth birthday of Motoo Kimura, edited by Tomoko Ohta and Kenichi Aoki (1985)
  • Tomoko Ohta and the Nearly Neutral Theories: The role of a female geneticist in the neutralist-selectionist controversy, Tomoko Y. Steen (1996) Ph.D. Dissertation. (CORNELL UNIVERSITY)[2]


  1. ^ "So-called egalitarian Japan is still honor-bound - The Japan Times". 9 November 2016.
  2. ^ a b Ohta, Tomoko (2012), "Tomoko Ohta", Current Biology, 22 (16): R618–R619, doi:10.1016/j.cub.2012.06.031, PMID 23082325
  3. ^ a b "National Institute of Genetics: OHTA, Tomoko - Professor Emeritus". NIG. Retrieved 20 April 2016.
  4. ^ Steen, TY. 2008 "The Case of Ohta Tomoko: A Woman Geneticist in the Neutralist-Selectionist Evolution Controversy." Historia Scientiarum, volume 18(2), pages, 172–184.
  5. ^ "National Institute of Genetics Feature: Our Leaders in Genetics". NIG. Archived from the original on 6 October 2011. Retrieved 5 July 2011.
  6. ^

Further reading[edit]

External links[edit]