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What sort of research
did you do in college? |
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| Yanagisawa (second from right) presents
some research to students of another university at the Ochanomizu
University festival. |
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In the autumn of my third year at college, I came across
a book on bacteriology by Werner Braun. I had heard from my father that
the most exciting research in biology was being carried out on bacteria
such as E. coli, viruses, and similar microorganisms. According to
this book, experiments had shown that when penicillin-resistant E. coli
bacteria were exposed to penicillin in increasing concentrations, the degree
of resistance increased by the same factor. I was struck by the strange
beauty of this. Why should resistance increase by integral factors instead
of gradually? It occurred to me how interesting it would be to perform a
similar experiment using hydrogen peroxide, and I chose this topic for my
graduation thesis.
None of the teachers at my university had worked with E. coli, and
the lab wasn't equipped with the sterile container that I needed for the
experiment, so I made one myself by constructing a wood frame 90 centimeters
on each side, covering it with plastic, and sterilized it by using an atomizer
to spray carbolic acid inside the box. I planned the experiment myself by
reading books that described experiments on E. coli. The results
bore out my prediction that E. coli would respond to increasing concentrations
of hydrogen peroxide in the same way.
As my fiancé was studying at
Columbia University, I traveled to the United States as soon as I graduated,
and we were married. I decided to continue my studies at Columbia as well,
working under Professor Francis Ryan, a molecular biologist and a friend
of my father's. |
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What did you study
in the United States? |
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| Conducting an experiment in Professor
Ryan's laboratory. |
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The 1960s were a period of great ferment in molecular
biology, and new discoveries were taking place one after another. It was
in 1962, while I was studying at Columbia, that James Watson, Maurice Wilkins,
and Francis Crick received the Nobel prize for their discovery of the structure
of the DNA molecule. Dr. Ryan's graduate students were trying to investigate
whether a mutation would occur in E. coli if a single molecule of
DNA were artificially replaced with another. But we did more than cutting-edge
research at Columbia. We were also required to learn everything about the
history of life science, beginning even before Mendel, the father of modern
genetics, and to understand modern biology in the context of the history
of science. By knowing the past, one can predict the future--this lesson
has helped me to understand the importance of preserving a frame of reference
for my own work and life. |
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What has been the
main focus of your research? |
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| Yanagisawa in the courtyard of the Museum
of Modern Art, New York, a new life stirring inside her. |
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After returning from the United States, I had two children,
and what with that and other duties, I spent seven years as a full-time
wife and mother. But in 1971, I returned to work as a researcher at
Mitsubishi Kasei Institute of Life Sciences (now the Mitsubishi Kagaku
Institute of Life Sciences). Having given birth, I was more interested in
human beings and how they develop, and I wished to do my research on mammals.
At the institute, I did research to determine how a certain mutation that
causes short tails in mice comes about.
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| With some foreign researchers. |
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The cause of the short tail is a mutation in what scientists
refer to as the T gene. If a mouse has the mutant T gene in one out of a
pair of chromosomes, the tail will be short; if the mutant gene is present
in both chromosomes, the embryo will not survive. I wrote a paper on the
role of the T gene in the embryonic development of mice, and it was published
in the American scholarly journal Developmental Biology in 1981.
Unfortunately, a few years later I began to experience a number of unexplained
symptoms--severe menstrual pain, bleeding, anemia, vomiting, abdominal pain,
numbness--for which I was hospitalized repeatedly and underwent several
operations. For a while, I continued my observations from my bed, looking
through the microscope as I lay on my side. But the symptoms grew worse,
and in 1983 I gave up research.
Seven years later, I heard that a team of American, German, and British
scientists had isolated the fragment of DNA that corresponds to the T gene.
Retrieving my mouse experiments from storage and rereading them, I suddenly
realized that they demonstrated that the T gene determined the mouse embryo's
antero-posterior axis. I quickly delivered a paper on the subject, and my
theory was greeted by Professor Dorothy Benett, an authority on the T gene,
as a cutting-edge theory of developmental biology.
Later it was discovered that the T gene was present in frogs (who have no
tails), fish, birds, and mammals, including human beings--in other words,
in all vertebrates. (Many scientists came to believe that the T gene controlled
the development of the backbone and surrounding bones and muscles, but this
theory was eventually exploded by the discovery that the gene is present
also in sea urchins, which have no backbone.) |
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