Tomoko Ohta

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 allelic 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 PhD.

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.

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.

• 1984 - Fellows of the American Academy of Arts and Sciences
• 1985 - Japan Academy Prize
• 2002 - Foreign Member of the National Academy of Sciences
• 2002 - Person of Cultural Merit
• 2015 - Crafoord Prize of the Royal Swedish Academy of Sciences (shared with Richard Lewontin)
• 2016 - Order of Culture

• 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)

• Ewens, Warren J. (2012). "James F. Crow and the Stochastic Theory of Population Genetics". Genetics. 190 (2): 287–290. doi:10.1534/genetics.111.135194.
• Ohta, Tomoko; Gillespie, John H. (April 1996). "Development of Neutral and Nearly Neutral Theories". Theoretical Population Biology. 49 (2): 128–142. CiteSeerX 10.1.1.332.2080. doi:10.1006/tpbi.1996.0007. PMID 8813019.
• Ohta, Tomoko (10 December 2002). "Near-neutrality in evolution of genes and gene regulation". Proceedings of the National Academy of Sciences of the United States of America. 99 (25): 16134–16137. Bibcode:2002PNAS...9916134O. doi:10.1073/pnas.252626899. PMC 138577. PMID 12461171.
• Steen, TY. (2008). "The Case of Ohta Tomoko: A Woman Geneticist in the Neutralist-Selectionist Evolution Controversy". Historia Scientiarum. 18 (2): 172–184.
• Steen, TY. (1996). "Always an excentric?: A Brief Biography of Motoo Kimura". Journal of Genetics. 75 (1): 19–25. doi:10.1007/BF02931748.

• "Profile of Tomoko Ohta". Perspectives on Molecular Evolution.