Your Majesties, Ladies, and Gentlemen:
It is a great honor to receive the 2002 International Prize for Biology,
which is for the field of evolutionary biology. I understand that His
Majesty the Emperor is an enthusiastic biologist and has published many
papers on the taxonomy and evolution of Gobioid fishes including a paper
on molecular phylogeny. This makes me especially happy to receive this
year's award as an evolutionary biologist.
When I was a college student, I read a number of books on evolution.
However, I was not particularly interested in this subject, because
evolutionary biology at that time was highly speculative and it was
difficult to prove or disprove various arguments presented for
explaining evolution. I was then interested in population genetics, in
which short-term evolution was studied by using mathematical theory and
experimental verification. I was particularly interested in developing
mathematical theory by which one could predict short-term genetic change
of biological populations.
It was in the 1960's and the 1970's that various molecular techniques
were introduced in the study of evolution. Before this time, the only
way to identify homologous genes between different individuals was to
conduct hybridization experiments, but in principle this could not be
done between different species. Therefore, most experimental studies of
population genetics or evolution were confined to individuals within
species. Introduction of the new molecular techniques radically changed
this situation. It removed the species barrier and made it possible to
study evolutionary change of genes between distantly related organisms
even between bacteria and humans. This opened up the new field of
molecular evolutionary biology. One of the pioneers who developed
various mathematical theories of molecular evolution was my mentor,
Professor Motoo Kimura, who was the recipient of the 1988 International
Prize for Biology.
Although the conceptual framework of molecular evolutionary biology was
laid out largely by Professor Kimura and others, it was still necessary
to develop statistical methods by which one can infer the evolutionary
histories of populations and species and test various evolutionary
theories with empirical data. I initiated this type of work around 1970
and tried to make evolutionary biology a testable science rather than a
speculative one. I continued this work for over 30 years and applied the
statistical methods developed to find some general principles of
During these years, I was very fortunate to have many students and
collaborators, who joined in my efforts to understand evolution at the
molecular level. I should also mention that the statistical study of
molecular evolution was initiated not only by my group but also by other
investigators, some of whom are attending this ceremony. I would like to
take this opportunity to thank all of them who participated in our joint
venture to make evolutionary biology a quantitative and
I have been a man of curiosity from the time of childhood. I feel very
happy when I find some explanation even for a small mystery. This is
especially so when I discover a simple rule underlying a seemingly
complicated phenomenon. In 1960 and 1961, I visited the United States
for the first time for over one year. At that time Japan was poor, and
it was important to improve the economic status. By contrast, the United
States was rich and allowed scientists to do both basic and applied
research. In fact, original research was strongly encouraged. This
environment inflamed my interest in doing research driven by curiosity,
and in 1969 I moved to the United States to do basic research.
Japan is now a rich country, and I understand both basic and applied
research is encouraged. I also hear that the universities and research
institutes in Japan are now under reorganization to enhance original
research and accountability to the public. With this new environment, I
am confident that in the near future Japan will play an important role
in the international scientific community as well as the world economy.
I am most grateful for the Selection Committee of the International
Prize for Biology for recognizing the importance of molecular study of
evolution and for selecting me as the recipient of this prestigious
award. I humbly accept this award as a representative of the many
scientists who have contributed to the progress of molecular
evolutionary biology during the last 30 years.
I am very grateful for all the nice words that have been said about me.
I also would like to thank all of you who have come here to attend the
award-presentation ceremony. I finally would like to thank my wife,
Nobuko, and my children, Keitaro and Maromi, for their patience and
understanding while I devoted a large portion of my life to scientific
research. Without their support and affection, I could not have
accomplished any significant work.