Tomoko Ohta facts for kids
Quick facts for kids
Tomoko Ohta
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| 太田 朋子, Ōta Tomoko | |
Tomoko Ohta
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原田 朋子, Harada Tomoko
7 September 1933 Miyoshi, Japan
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| Nationality | Japanese |
| Alma mater | North Carolina State University University of Tokyo |
| Known for | Development of neutral theory of molecular evolution, and nearly neutral theory |
| Spouse(s) | Yasuo Ohta (m.1960-1972) |
| Awards | Japan Academy Prize (1985) Weldon Memorial Prize (1986) Crafoord Prize (2015) Japan's Order of Culture (2016) |
| Scientific career | |
| Fields | Evolutionary biology genetics |
| Institutions | National Institute of Genetics North Carolina State University Kihara Institute for Biological Research |
| Doctoral advisor | Ken-Ichi Kojima |
| Other academic advisors | Motoo Kimura Hitoshi Kihara |
Tomoko Ohta (太田 朋子, Ōta Tomoko, born Tomoko Harada 原田 朋子 7 September 1933, Miyoshi, Aichi) is a Japanese scientist. She is a Professor Emeritus at the National Institute of Genetics. This means she is a retired professor who still holds her title. Dr. Ohta studies how genes change over time in groups of living things. She is famous for her "nearly neutral theory of evolution".
Tomoko Ohta has won many important awards. These include Japan's Order of Culture in 2016. In 2015, she shared the Crafoord Prize with Richard Lewontin. They won for their important work on understanding genetic variation.
Contents
Early Life and Education
Tomoko Ohta was born in 1933 near Nagoya, Japan. She grew up in Miyoshi-cho in Aichi Prefecture. When World War II ended, she was in the 6th grade. After the war, many changes happened in Japan. Schools started to have both boys and girls learning together.
Ohta went to junior high school in Toyota. She became very interested in math and physics. After high school, she wanted to study medicine. However, she did not pass the medical school exam. She then went to the agriculture department at the University of Tokyo. There, she studied horticulture, which is about growing plants. She graduated in 1956.
After working for a publishing company, Ohta got a job at the Kihara Institute for Biological Research. At this institute, she studied the cytogenetics of wheat and sugar beets. Cytogenetics is the study of chromosomes in cells.
Studying Abroad
A scientist named Hitoshi Kihara gave Ohta a chance to study in another country. In 1962, she started a graduate program at North Carolina State University in the United States. She received help from a Fulbright scholarship. At first, she planned to study plant cytogenetics. But she changed her focus to population genetics. This field looks at how genes change in groups of living things over time.
She worked with her professor, Ken-Ichi Kojima. They studied problems in how genes change randomly in populations. Ohta finished her PhD in 1966.
Career in Genetics
In 1967, Tomoko Ohta returned to Japan. She got a research job at Japan’s National Institute of Genetics (NIG). She worked with Motoo Kimura, who was the only expert in theoretical population genetics in Japan at that time.
Ohta was promoted to a research position at NIG in 1969. She stayed there until 1996. In 1984, she became a Full Professor in the Department of Population Genetics at NIG. She became the head of that department in 1988. From 1989 to 1991, she was the Vice-Director of the National Institute of Genetics. In 1994, Ohta also served as the Vice-President of the Society for the Study of Evolution.
Key Research and Theories
In the early 1960s, scientists thought that changes in genes (mutations) were either very bad or very good. Bad mutations were thought to disappear. Good mutations were thought to spread in a population. Because of this, scientists expected all individuals in a group to be very similar.
However, in 1966, Richard Lewontin and John Lee Hubby found something different. They saw much more genetic variation among individuals than expected. Motoo Kimura suggested an idea called the neutral theory of evolution. This theory said that some gene changes were neither good nor bad. They were "neutral" and not affected by natural selection.
Developing the Nearly Neutral Theory
Tomoko Ohta worked with Kimura on the neutral theory. But she believed that dividing mutations into only "good," "neutral," or "harmful" was too simple. She thought it did not fully explain what scientists observed.
Ohta believed that mutations that were "nearly neutral" still played a big role in evolution. These mutations were not completely neutral, but they were not very harmful either. She first created a model called the "slightly deleterious model." Then she made a more general idea, the nearly neutral theory of evolution.
Her theory was different from her mentor Kimura's idea. But they were able to discuss their ideas strongly while staying friends.
Understanding Nearly Neutral Mutations
Ohta's theory introduced a new way to think about how mutations become common. Most mutations that affect proteins are harmful. But if they are only "slightly harmful" (nearly neutral), they can still stay in a population.
Ohta also looked at how chance and population size matter. She showed that population size is important. In a smaller group of living things, chance has a bigger effect. This means that natural selection works less well. So, mutations that are slightly harmful can become common more easily in small populations. This happens through a process called genetic drift.
In 1974, Kimura and Ohta suggested five general rules that might affect how genes change over time.
When Ohta first shared her Nearly Neutral theory, it was hard to get other scientists to accept it. But in the 1990s, more and more evidence supported her theory. Even more proof has come out in the 21st century. Her theory is now widely accepted.
"The nearly neutral theory... still constitutes an excellent starting point for further theoretical developments."
Awards and Recognition
Tomoko Ohta's work in how genes change has been recognized around the world.
- 1981 - First Saruhashi Prize
- 1984 - International Honorary Member, American Academy of Arts and Sciences
- 1985 - Japan Academy Prize for her studies on population genetics
- 1986 - Avon Special Prize for Women
- 1986 - Weldon Memorial Prize, University of Oxford
- 2002 - Foreign Member of the United States National Academy of Sciences
- 2002 - Person of Cultural Merit, given by the Emperor of Japan
- 2015 - Crafoord Prize (shared with Richard Lewontin)
- 2016 - Order of Culture, given by the Emperor of Japan
- 2018 - Society for Molecular Biology and Evolution (SMBE) Motoo Kimura Lifetime Contribution Award
See also
In Spanish: Tomoko Ohta para niños
