Dunn, L. C. (Leslie Clarence), 1893-1974

Geneticist.

Leslie C. Dunn was a geneticist.

Papers of James V. Neel, pioneering human population geneticist and professor in the Department of Human Genetics, University of Michigan Medical School. Curt Stern's first graduate student at the University of Rochester, and a post-doctoral student under Theodosius Dobzhansky, Neel began his career as a Drosophila geneticist, but after taking his first professional appointment as an assistant professor at Dartmouth, decided to alter his course into human genetics. Reasoning that he needed a solid medical education to complement his genetical training, he returned to Rochester in 1942 to study for an MD.

Like all medical students during the Second World War, Neel was inducted into military service. Rochester was the base for studies in radiation biology associated with the Manhattan Project, and at the end of the war, with Neel still in the military, a chance friendship with the adjutant to the head of the project resulted in Neel's appointment to help organize a genetical survey of the atomic bomb survivors. In 1946-1947, Neel lived in Hiroshima, organizing this project, part of the Atomic Bomb Casualty Committee (ABCC), and he maintained a close connection to the study until his death. His work in Japan mushroomed, too, into a series of related projects into the biology and genetics of consanguinity, among other topics.

While at Rochester, Neel also began to establish a name for himself in other areas of human genetics. As a resident at Rochester's Strong Memorial Hospital, Neel encountered a case of thalassemia, and reading the medical literature, he became convinced that it was a genetic recessive disease. Over a span of five years, he delineated the genetic basis of haemoglobin diseases - first thalassemia, then sickle cell disease - in the process, helping to precipitate the revolution in biochemical genetics of the 1950s through 1970s. Neel's work also encompassed the evolutionary implications for these diseases, implanting balanced polymorphism and heterozygote advantage into the vocabularies of evolutionary biologists. Neel's studies of thalassemia and sickle cell disease were recognized with the receipt of the Lasker Award in 1955.

In the late 1950s, Neel entered into a third major set of projects, turning to extensive field studies in population genetics. Recognizing that the number of human populations isolated from modern medicines and modern technology was rapidly dwindling, Neel embarked on an ambitious genetic survey of the comparatively "primitive" Xavante of Brazil and, later, the Yanomamo of the Brazilian-Venezuelan borderlands. These studies, carried out over the course of more than a decade, and involving even longer spans of laboratory work, constitute the first and most comprehensive studies of human population and breeding structure and genetic diseases among "primitive" peoples. Dr. Neel died in February, 2000.

L.C. Dunn was a seminal figure in the 20th century emergence of developmental genetics. His T-locus work with the mouse established a number of important genetic principles, including ideas of gene interaction, the distribution of alleles in wild populations, and the factors that influence fertility, and his influence spread, in part, through his widely used genetics textbook, Principles of Genetics (N.Y.: McGraw Hill, 1925), written in collaboration with Edmund Ware Sinnott (and later Theodosius Dobzhansky). Other significant works authored or co-authored by Dunn include Heredity, Race and Society (1946), and A Short History of Genetics (1965).

Leslie Clarence Dunn was born in Buffalo, New York in 1893, the son of Clarence Leslie and Mary Eliza (Booth) Dunn. At Dartmouth College from 1911-1915, he applied himself to the study of zoology under John H. Gerould, with whom he maintained life-long ties. It was through Gerould that he obtained a copy of T.H. Morgan's Heredity and Sex in 1914, a book that significantly influenced the course of Dunn's professional career. Smitten with genetics, after graduating from Dartmouth, Dunn applied to study under Morgan at Columbia University, but was turned away from the already overcrowded fly lab. Instead, he took an assistantship to work with William E. Castle at Harvard, where he was assigned charge of the laboratory for breeding Drosophila . His first significant work was a study of sex-linked genes in Drosophila, but when his results were "scooped" by a student of Morgan, he turned to work on linked genes in mice and rats. He published eight papers on rodent genetics between 1916 and 1921, including his dissertation Linkage in Mice and Rats (1920).

Dunn's graduate work was interrupted by the outbreak of the First World War, during which he was commissioned as a First Lieutenant in the American Expeditionary Force in France. He married Louise Porter, a Smith College graduate, in 1918, with whom he had two sons, Robert Leslie (b.1921) and Stephen Porter (b.1928).

After his release from the Army, Dunn's first professional position was serving as poultry geneticist at the Agricultural Experiment Station in Storrs, Connecticut. His time there (1920-1928) was productive, resulting in over forty papers on poultry genetics as well as the first edition of Principles of Genetics . One of the most widely used genetics textbooks of its time, it went into five editions and was translated into numerous foreign languages.

In 1929, Dunn was tapped by Columbia to fill the post vacated by Morgan, who had departed for the California Institute of Technology. As a full professor in the Zoology Department, Dunn quickly demonstrated his abilities as a teacher as well as a researcher, mentoring Simone Gluecksohn-Waelsch and Dorothea Bennett, among many others.

Because life in the heart of New York City precluded large-scale research projects on poultry, Dunn revived his research on rodents and fruit flies, although he continued to keep hand in poultry, working in concert with Walter Landauer at Storrs. Initially, Dunn's mouse work at Columbia focussed on the problem of the inheritance of pigmentation, but his interest in congenital abnormalities soon led him to branch out into a study of lethal and semi-lethal mutants in research animals and compare them to similar conditions in humans. His work on T-locus mutants occupied over forty years and established him as a leader in developmental genetics. His research also verged on population genetics: he studied colonies of mice in both the laboratory and the field, establishing the principle that gametic selection could be even more powerful than natural selection.

Possessed of a strong social conscience honed by association with his fellow Columbians Theodosius Dobzhansky and Franz Boas, Dunn took an active interest in human genetics and its social implications. During the 1920s and 1930s, he spoke out against the misapplication of genetics to justify mistreatment of oppressed groups of people, including blacks and Jews. He established an Institute for the Study of Human Variation at Columbia in the 1950s. Although the Institute was short-lived, several key research projects resulted from it, including Dunn's "The Jewish Community in Rome." The Institute also spawned a number of students who have made important contributions to human genetics, including R. H. Osborne and W. S. Pollitzer.

In 1946, Dunn and Theodosius Dobzhansky collaborated on Heredity, Race, and Society, an immensely important book that cast a genetist's eye on the race problem in America. Taking cues from the work of Ashley Montagu, Franz Boas, and others, the work was an important study of racial variation, but also a major statement on the vexing question coopted by eugenicists of the relationship between nature and nurture. "We come into the world," they wrote, "as a bundle of possibilities bequeathed to us by our parents and other ancestors. Our nurture comes from the world about us. What happens to the nurture that comes in depends, however, on the nature that receives it." Dunn and Dobzhansky concluded that nature and nurture were inseparably intertwined and integral to the shaping of human capacities, rendering the dichotomy between them not only misleading, but fundamentally wrong. In 1951 Dunn was selected to write the UNESCO report Race and Biology, which carried this point further.

Dunn's personal friendships with scientists and their families from around the world often served as a springboard into other activities. During a tour of Europe in 1927, for example, Dunn visited Russia as the guest of A.S. Serebrovsky. As a result of the experience, Dunn became a founder and active member of the American-Soviet Friendship Council and, during World War II, was the president of the American-Soviet Science Society. Deeply disturbed by the rise of Nazism, Dunn became an active member of the Emergency Committee for German Scholars (later called the Emergency Committee in Aid of Displaced Scholars) in 1933, helping refugee scholars to relocate in American. Not surprisingly, Dunn's interest in international collaboration brought him under severe criticism. The organizations in which he took part were deemed subversive in the reactionary environment of the late 1940s and 1950s, and Dunn himself was accused of being a Communist.

Dunn's internationalism and interest in Russian science drew him into the Lysenko controversy of the 1950s. The "dictator" of Soviet biology during the Stalinist era and beyond, Lysenko espoused eccentric ideas about agriculture and genetics, and led a wholesale assault on modern genetics theories. The Russian language edition of Dunn's Principles of Genetics had sold more copies in Russian in the 1930s than the English original, however Lysenko banned the book.

Dunn pursued his interest in genetics to the end of his life. When he retired from Columbia in 1962, he was granted emeritus status and set up a "mouse lab" to continue work in collaboration with his former student, Dorothea Bennett. Toward the end of his life he developed an interest in the history of science, writing A Short History of Genetics in 1965. The donation of his papers to the American Philosophical Society helped to establish the APS archives as a premier facility for the study of the history of genetics.

Dunn was a member of the American Philosophical Society (1943), the National Academy of Sciences (1943), the American Academy of Arts and Sciences, the Norwegian Academy of Sciences, and the Italian Academia Pataviana. He was a founder of the Genetics Society of America, its President in 1932, and managing editor of its journal, Genetics, from 1935 to 1940. He was also a member of the American Society of Naturalists, its President in 1960, and editor of its journal The American Naturalist, from 1951 to 1960. He was a member of the American Society of Human Genetics, and its President in 1961. He also was a visiting professor at the Genetics Institute of the University of Oslo, Norway in 1934-35, at the Instituto Superiore de Sanita, Rome, in 1953-54, and at University College, London in 1960-61.