Yuichiro Hiraizumi was born in Odate, Akita-Ken, Japan on April
10, 1927, the son of Sue and Katsuro Hiraizumi. He died in Austin
on January 27, 2003. The path between these distant cities was
traveled by a person of extraordinary intelligence, determination,
and accomplishment. As a child, he contracted poliomyelitis,
which left him unable to walk normally. This presented a problem
when it became time to enroll in a university. At that time,
Japanese universities required that students be physically fit,
a requirement that was tested by completing a foot race within
a specified time. This was a large challenge for Yuichiro. Although
he failed to qualify several times, eventually his determination
won out, and he was admitted, completing a bachelor of science
degree at Hokkaido University (Sopporo) in 1952.
Following his B.S. degree, he entered the graduate program in
genetics at Hokkaido, where he studied for four years. Three
papers in plant genetics were published from this period. In
1956, he moved to the University of Wisconsin (Madison) to continue
work toward a doctorate with James Crow. The original problem
was a study of the fitness of chromosomes extracted from a wild
population of
Drosophila melanogaster. Within a few
months, he had discovered a remarkable phenomenon, a gene that
is not transmitted in Mendelian proportions. Fortunately, Larry
Sandler came to Wisconsin the next year as a postdoctoral fellow,
and the two of them became a remarkably productive team. Since
the 1900 rediscovery of Mendel’s work, it has been common
knowledge that, in eukaryotes (including humans and fruit flies),
genes on a pair of homologous chromosomes are distributed equally
and randomly into germ cells. If the germ cells from two parents
combine at random, the familiar Mendelian ratios are observed
in the absence of differential survival of the various gene combinations.
The process of separation of homologous genes during germ cell
formation is called
segregation. Hiraizumi and Sandler
demonstrated that the aberrant transmission, which they called
segregation
distortion, or
meiotic drive, occurs in the formation
of germ cells. This heretical finding was reported in detail
in a series of nine papers in major journals in 1959-1961 and
became a major research topic in other laboratories in the years
following. Variant segregation also became a major theme of Hiraizumi’s
later research, whether due to meiotic drive or to other mechanisms.
In 1960, Hiraizumi's Wisconsin research qualified him for the
degree of doctor of science from Osaka University (Japan), a
degree based on research accomplishments. That year he joined
the staff of the National Institute of Genetics in Mishima, Japan,
one of the outstanding centers for genetic research in the world.
There he worked on
Drosophila, on
Trillium (which
he had studied earlier), and on segregation of various genes
in humans, particularly the ABO blood groups. In 1965, he was
a visiting associate professor at the University of Hawaii in
Honolulu, becoming a permanent faculty member in 1966. In 1967
while visiting Wisconsin he showed (with Hartl and Crow) that
segregation distortion was due to nonfunctional sperm. In 1969
he moved to the Department of Zoology at The University of Texas
at Austin, where he remained for the remainder of his professional
life. This included promotion to professor in 1971. In 1987 he
was named the T. S. Painter Centennial Professor of Genetics,
and, at the time of his retirement in 1996, he was awarded the
title of T. S. Painter Professor Emeritus.
A full description of Hiraizumi’s research would be difficult
to write and more so to read. He tackled experimentally demanding
problems that required skilled analysis and meticulous attention
to observational details. This combination of talents led to
another unanticipated and significant discovery: recombination
in
Drosophila males. Although crossing over in males
is the normal pattern for most species, it does not occur in
Drosophila.
Hiraizumi demonstrated, however, that it does occur as a rare
event. Furthermore, he found a wild strain in South Texas in
which it occurs with high frequency. With his customary sense
of humor, he named the strain T-007, this at a time of great
popularity of James Bond. The discovery that, under certain conditions,
recombination can occur in
Drosophila males was the
beginning of studies relating this observation to the so-called
P-M hybrid dysgenesis system involving the transposable element
P.
An account of some of Hiraizumi’s many contributions was
published on the fortieth anniversary of the discovery of segregation
distortion (B. Ganetsky, “Yuichiro Hiraizumi and Forty
Years of Segregation Distortion,”
Genetics, v.
152, pp. 1-4, 1999.)
A measure of the great respect in which Hiraizumi was regarded
is his history of external grant support. When he came to UT
Austin, he applied for and received a grant from the National
Institutes of Health to support his studies of genetic segregation.
Such applications are reviewed rigorously by peers from other
institutions. His initial grant for three years was renewed,
eventually becoming five-year grants, which continued under the
same title until his retirement.
Hiraizumi was an outstanding teacher as well as a research investigator.
Although his accent may have been an initial challenge to native
Texans with modest exposure to Japanese, his undergraduate students
soon realized his strong commitment to help them learn the sometimes
confusing topic of genetics. He was always available to help
them understand whatever problem presented a challenge. His effectiveness
as a teacher for undergraduate students was recognized in 1986
with a College of Natural Sciences Teaching Excellence Award.
He was also an excellent mentor for graduate students, having
supervised seven Ph.D. and five M.A. degrees during his career.
Hiraizumi was a good colleague and citizen. He did his share
of departmental and committee work, always with the thoroughness
that characterized his other activities. In several instances,
he became an unofficial mentor for graduate students who needed
assistance with their research. He was generous in providing
stocks, materials, and other support for undergraduate laboratories
for which he had no formal responsibility.
Yuichiro and his wife, Mitsuko, had a son, Kazuo, and a daughter,
Midori. Yuichiro’s favorite form of relaxation was fishing
in the Gulf of Mexico with his family. He added to that the performance
of magic tricks for his children and later for his grandchildren,
an activity in which he apparently was rather adept. Mitsuko
was a talented artist who enjoyed introducing westerners to the
cultural traditions of Japan. She preceded Yuichiro in death
in 1993.
<signed>
Larry R. Faulkner, President
The University of Texas at Austin
<signed>
Sue Alexander Greninger, Secretary
The General Faculty
