Ohta’s outstanding talent and skill to achieve success
as a woman in the scientific arena was deeply rooted in her
childhood experiences and environment provided by a broad-minded
father, Mamoru Harada, and mentors, Hitoshi Kihara, Ken Kojima,
and Motoo Kimura. Their guidance provided Ohta with a firm
foundation and credibility from which to enter her name in
the major evolutionary dispute, the selectionist-neutralist
Although Ohta studied on horticulture at the Agriculture
Department of Japan’s top university, Tokyo University,
Ohta’s hard step toward a world-class geneticist begun
when she started to work at Hitoshi Kihara’s Institute
in Yokohama. Using this experience as a steppingstone, Ohta
received a Fullbright Scholarship to study as a Ph.D. student
at North Carolina State University under the guidance of Ken
Kojima. Her contemporaries at NC State at that time were:
Bruce Weir and Henry Shaffer. The late Terumi Mukai was also
a faculty member there.
In 1967, completing her Ph.D. degree, Ohta returned to Japan
and visited Motoo Kimura at Japan’s National Institute
of Genetics (NIG) seeking a job opportunity there. Kimura
was at the final preparation for his work on the neutral theory
to present at the domestic genetics society meeting. Ohta
quickly became the major work force to collect data to complete
In spite of several attractive job offers over the years,
Ohta spent the rest of her career at Japan’s NIG. Ohta’s
work in the field of molecular evolution has been recognized
internationally, as attested to by her recent awards and offices.
In April of 1984, Ohta became a Full Professor in the Department
of Population Genetics at Japan’s National Institute
of Genetics. In May of that year, she was appointed a Foreign
Member of the American Academy of Arts and Sciences. In 1985,
she received the Japan Academy Award and, in 1987, the Weldon
Memorial Prize. Ohta became Head of Department of Population
Genetics at NIG in 1988, and served as the Vice-Director of
the National Institute of Genetics from 1989 to 1991. She
was appointed to be Vice-President of the Evolution Society
in 1993. In 2002, Ohta was selected to be a Foreign Member
of the National Academy of Science of the United States, and
received the “Person of Cultural Merit” from Japanese
emperor in 2002. She also received special prizes as a distinguished
female scholar. She was the inaugural recipient of Saruhashi
Prize from the Society for the Bright Future of Women Scientists
in 1981, as well as the Avon Special Prize for Women in 1986.
This Profile was written by Tomoko Y. Steen. It was last
updated on 9/9/2004.
- T. Ohta and M. Kimura, "Linkage Disequilibrium due
to random genetic drift," Genetical Research
13 (1969): 47-55.
- T. Ohta and M. Kimura, "Development of associative
overdominance through linkage disequilibrium in finite populations,"
Genetical Research 16 (1970): 165-177.
- T. Ohta, "Associative overdominance caused by linked
detrimental mutations," Genetical Research 18
- T. Ohta and M. Kimura, "Linkage disequilibrium between
two segregating nucleotide sites under the steady flux of
mutations in a finite population," Genetics
68 (1971): 571-580.
- T. Ohta and M. Kimura, "On the constancy of the evolutionary
rate of cistrons," Journal of Molecular Evolution
1 (1971): 18-25.
- T. Ohta and M. Kimura, "Functional organization of
genetic material as a product of molecular evolution,"
Nature 233 (1971): 118-119.
- T. Ohta, "Evolutionary rate of cistrons and DNA divergence,"
Journal of Molecular Evolution 1 (1972): 150-157.
- T. Ohta, "Population size and rate of evolutiuon,"
Journal of Molecular Evolution 1 (1972); 305-314.
- T. Ohta, "Slightly deliterious mutant substitutions
in evolution," Nature 246 (1973): 96-98.
- T. Ohta and M. Kimura, "A model of mutation appropriate
to estimate the number of electrophoretically detectable
alleles in a finite population," Genetical Research
22 (1973): 201-204.
- T. Ohta, "Mutational pressure as the main case of
molecular evolution and polymorphism," Nature
252 (1974): 351-354.
- T. Ohta and M. Kimura, "Theoretical analysis of electrophoretically
detectable polymorphisms: Models of very slightly deliterious
mutations," American Naturalist 109 (1975):
- T. Ohta and M. Kimura, "The effect of selected linked
locus on heterozygosity of neutral alleles (the hitch-hicking
effect)," Genetical Research 25 (1975): 313-326.
- T. Ohta, "Simple model for treating evolution of
multigene families," Nature 263 (1976): 74-76.
- T. Ohta, "Role of very slight deleterious mutations
in molecular evolution and polymorphism," Theoretical
Population Biology 10 (1976): 254-275.
- T. Ohta, "Extension to the neutral mutation random
drift hypothesis," in M. Kimura (ed.), Proceedings
of the Second Taniguchi International Symposium on Biophysics
(1977), pp. 148-167.
- T. Ohta, "Theoretical population genetics of repeated
genes forming multigene families," Genetics
88 (1978): 845-861.
- T. Ohta, "Population genetics of selfish DNA,"
Nature 292 (1981): 648-649.
- T. Ohta, "Linkage disequilibrium with the island
model," Genetics 101 (1982): 139-155.
- T. Ohta, "On the evolution of multigene families,"
Theoretical Population Biology 23 (1983): 216-240.
- T. Ohta, "Time until fixation of a mutant belonging
to a multigene family," Genetical Research 41
- T. Ohta, "Simulating evolution by gene duplication,"
Genetics 115 (1987): 207-213.
- T. Ohta, "Very slightly deleterious mutations and
the molecular clock," Journal of Molecular Evolution
26 (1987): 1-7.
- T. Ohta, "Time for acquiring and new gene by duplication,"
PNAS 85 (1988): 3509-3512.
- T. Ohta, "Evolution by gene duplication and compensatory
advantageous mutations," Genetics 120 (1988):
- T. Ohta and H. Tachida, "Theoretical study of near
neutrality. I. Heterozygosity and rate of mutant substitution,"
Genetics 126 (1990): 219-229.
- T. Ohta, " Multigene families and the evolution of
complexity," Journal of Molecular Evolution
33 (1991): 34-41.
- T. Ohta, "Theoretical study of near neutrality. II.
Effect of subdivided population structure with local extinction
and recolonization," Genetics 130 (1992): 917-923.
- T. Ohta, "The nearly neutral theory of molecular
evolution," Annual Review of Ecology and Systematics
23 (1992): 263-286.
- T. Ohta, "The meaning of natural selection revisited
at the molecular level," TREE 7 (1992): 311-312.
- T. Ohta, "Pattern of nucleotide substitutions in
growth hormone-prolactin gene family: A paradigm for evolution
by gene duplication," Genetics 134 (1993): 1271-1276.
- T. Ohta, "On hypervariability at the reactive center
of proteolytic enzymes and their inhibitors," Journal
of Molecular Evolution 39 (1994): 614-619.
- T. Ohta, "Synonymous and nonsynonymous substitutions
in mammalian genes and the nearly neutral theory,"
Journal of Molecular Evolution 40 (1995): 56-63.
- T. Ohta and John Gillespie, "Development of Neutral and
Nearly Neutral Theories," Theoretical Population Genetics
49 (1996): 128-142.
- T. Ohta, "More on the Neutralist-Selectionist Debate,"
Bioessays (1997): 359-360.
- T. Ohta, "Motoo Kimura," Annual Review of
Genetics, 30 (1997): 1-5.