A Guide to the Genetics Collections at the APS
Major Collections

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Curt Stern Papers

b.Aug.30,1902, Hamburg, Germany. d.Oct.23,1981, Berkeley, Calif. Father, Earned S. Stern; dealer in antiques, dental supplies. Mother, Anna Liebrecht (S.), school teacher. m. Evelyn Sommerfield, Oct. 29, 1931. Children, Hildegard, Holly Elisabeth, Barbara Ellen. U.S. naturalized, 1939.

U. Berlin, Ph.D., 1923. Investigator, Kaiser-Wilhelm Inst. für Biol., Abt. Goldschmidt, 1923-33. Res. assoc. zool., U. Rochester, 1933-35; asst. prof., 1935-37; assoc. prof., 1937-41; prof. and chmn. dept., 1941-47; chmn., div. biol. sci., 1941-47. Prof. zool., U. Gal., Berkeley, 1947-70; prof. genetics, 1958-70; emer. prof, 1970-81. Fellow, Intnatl. Educ. Ed., Columbia U., 1924-26. Privatdozent, U. Berlin, 1928-33. Fellow, Rockefeller Found., Gal. Inst. Tech., 193233. Visit. prof., Western Reserve U., 1932. Vis. lect., Columbia U., 1944. Visit. prof., U. Paris, 1951. National Sigma Xi Lecturer, 1952-53. Guggenheim Fellow, 1955;1963. Lecturer on genetics, Amer. Inst. Biol. Sci. Film Course, early 1960s (12 films). Prather Lectures, Harvard U., 1965. Memb. adv. com. biol. & med. AEC, 1950-55.

BIOG.
B. Glass, Ybk. Amer. Philos. Soc. 1982:514-20. J.V. Neel, Biog. Mem. Natl. Acad. Sci. 56:442-473 (1987). Amer. Men of Sci.; Who's Who in America 34:2043; Who's Who in the World, 2nd ed., 949. Autobiographical sketch in Stern Papers.

BIBLIOG.
See J.V. Neel, Biog. Mem. Natl. Acad. Sci., op. cit.

BOOKS.
Multiple Allelie, 1930. Faktorenkoppelung and Faktorenaustausch, 1933. Principles of Human Genetics, 1949; 1960; 1973. The Origin of Genetics (with Eva Sherwood), 1966. Genetic Mosaics and Other Essays, 1968.

SCIENTIFIC OFFICES.
Genetics Soc. Amer., pres., 1950; Amer. Soc. Human Genetics, pres., 1957; Amer. Soc. Zoologists, pres., 1962.

EDITORIAL POSTS.
Editor, Genetics, 1947-51. Edit. Ed., Advances in Genetics, Cytogenetics, Humangenetik.

HONORS AND AWARDS.
Sc.D., McGill U., 1958. D. Rerum Naturae, U. München, 1972. Pres., Thirteenth International Congress of Genetics (Berkeley), 1974. Memb., National Academy of Sciences, U.S.A., 1948; Amer. Philos. Soc., 1954; Amer. Acad. Arts & Sciences, 1959. Amer. Soc. Naturalists; Sigma Xi. Kimber Gold Medal, Genetics, Natl. Acad. Sci., 1963. Mendel Silver Medal, Czechoslovakian Acad. Sci., 1965. Fred Lyman Adair Award, Amer. Gynecol. Soc., 1967. Allan Award, Amer. Soc. Human Genetics, 1974.

THE STERN PAPERS.
The Curt Stern Papers fill 49 boxes and comprise about 18,000 items. Of these, 37 consist of letters and notes; 1 contains notebooks; 1, photographs; 1, newspaper and magazine clippings; 2, various manuscripts; 3, a collection of Stern's own publications (reprints); and 4, a collection of reprints frequently consulted by him. Presented by Mrs. Curt Stern, 1981-82.

Curt Stern's unpublished autobiographical sketch, contained among the Curt Stern papers, tells much about his early years. His father was a dealer in antiques, and later in dental supplies. His mother was a school teacher. Neither of them seems to have been very scientifically inclined, but they placed no obstacle in the way of Curt's boyhood interest in capturing lizards in the vicinity of Hamburg, Germany, where they lived, and in observing their habits after bringing them home; or in his collecting of rabbit skulls, or observing the microscopic animals of ponds and streams. His mother, especially, to quote Curt's own words, "fostered in me a desire to join the ranks of scientists. Her ambition spilled over to me."

At the University of Berlin Stern took a course in zoology taught by the renowned biologist Max Hartmann. He thus became confirmed in his selection of biology. As Stern entered upon graduate study, it was Hartmann who directed his thesis research, an excellent piece of work on the process of mitosis in one of the Heliozoa (Protozoa). After receiving his doctorate in 1923, at the very early age of twenty-one, Stern became an "Assistent" in Richard Goldschmidt's division of the Kaiser-Wilhelm Institut für Biologie in Berlin-Dahlem. Goldschmidt was already a geneticist of international renown, especially famed for his studies of the geographical variation of genetic types of the gypsy moth, Lymannia dispar, in Japan. These variations included modifications of the strength of the sex determining factors, and threw light on the evolution of geographic races into species -- or so it was thought at the rime. Goldschmidt had also published a very influential book on the physiological basis of gene action during the course of an animal's development.

At the time, however, Goldschmidt had remained unconvinced of the truth of the novel ideas of gene linkage within chromosomes, and the mapping of gene loci by the study of crossing over frequencies. He attacked the views of T. H. Morgan and his students at Columbia University in a paper that Curt Stern, upon reading, felt was quite wrong, and Goldschmidr became aware of this. It was therefore with great amazement that, not too long after, Stern was asked by Goldschmidt whether he would like to go to America to work under Morgan in Drosophila genetics. The International Education Board, supplied with funds from the Rockefeller Foundation, had established some fellowships to enable promising young European scholars to spend one or more years of postdoctoral research in the United States. Stern, much touched by Goldschmidt's magnanimity, applied and was accepted. Thus, in 1924, he arrived in New York to commence a momentous career in genetics.

His first Drosophila problem was to study the inheritance and sexually conditioned manifestation of a mutant recessive gene that produced shortened ("bobbed") bristles on female flies, but not on males. This peculiarity was solved by finding that in females which, because of non-disjunction of the X-chromosomes during meiosis, acquired a Y-chromosome, the bobbed character was suppressed, as in males. Clearly, the Y-chromosome, normally found only in males, must carry a suppressor of the bobbed mutant, a normal allele of it. This was the first evidence obtained by anyone that the Y chromosome is not entirely "empty" of ordinary genes. Stern's research then led him to explore the effects of fragmentation of the Y-chromosome because of a translocation, and possession by males of either the terminal part alone, or the distal part alone, as well as both together. The two former classes of males are sterile; those with both parts, like those with an intact Y chromosome, are fertile. These studies led Stern into the analysis that was to make him most famous as a young scientist. But that was research completed only after Stern had returned to Goldschmidt's laboratory in 1926.

This ingenious experiment was one of two, almost simultaneous, that demonstrated the cytological basis of crossing over. The other was an equally famous piece of experimental work by Harriet Creighton and Barbara McClintock, young maize geneticists from R. A. Emerson's laboratory at Cornell University. Both experiments were brilliant examples of the power of cytological work combined with genetics, and together proved once and for all the validity of the Chromosome Theory of Heredity, the Linear Order of the Genes within each chromosome, and physical exchange of segments by crossing over between homologous chromosomes. Stern's demonstration, however, was the more elegant of the two, and the more convincing, because he used not only homologous X-chromosomes that were cytologically distinguishable (one of them was broken in two by a translocation; the other had a long translocated piece of chromosome attached to it at the spindle fiber end), but were also genetically marked with mutant genes (carnation eye color and Bar eye shape). Hence a gene recombination between the marker genes led to predictions about the aberrant chromosome types that were to be expected in the crossover flies; and conversely, when a particular chromosome configuration that had not been present in the parents and could only arise by a physical exchange between parts of the homologous chromomes was found, it could be predicted what the phenotypes of the crossover offspring would be. There was never a discrepancy between prediction and finding. This was one of the truly great intellectual steps in the development of modern biology.

In Berlin, Stern continued his studies of the action upon the phenotype of the bobbed gene and its alleles. By obtaining, through non-disjunction, flies that had one or two Y-chromosomes carrying bobbed instead of the normal allele, he determined that a fly with three bobbed alleles has bristles longer (more normal) than a fly with two bobbed alleles. And a fly with four bobbed alleles possessed practically normal bristles. The conclusion forced on one is that each bobbed gene is doing the same thing, physiologically and developmentally, as the normal allele, but is weaker in effect. It takes four bobbed genes in a fly to make bristles like those made by two bobbed genes ordinarily. These were the first studies made by Stern of the effects of gene dosage and compensation during development, a field that he was to make especially his own in later years.

While at Dahlem in these years, Stern produced three remarkable reviews, including his first two among the books listed above. The first was a review of the significant steps in the establishment of the chromosome theory of heredity. The second was a review of multiple allelism, the phenomenon of the coexistence in a population of three or more different alleles of the same gene. When two different alleles are present in an individual, they may interact in the familiar pattern of dominance/recessivity, as in Mendel's famous peas. Or they may interact to produce a graded intermixture ("blending"). Or they may produce entirely independent effects on the phenotype, in an additive way. The most familiar example of the latter is found in the human ABO blood groups. A person with allele A in one chromosome and the allele B in the other will be of type AB, as neither allele interferes with the production of the characteristic antigen of the other. The third review was a thorough examination of the genetic evidence for linkage and crossing over (Faktorenkoppelung und Faktorenaustausch), the field to which Stern had added the capstone by his demonstration of the physical reality of crossing over between homologous chromosomes during the meiosis of the germ cells and the parallelism of genetic and cytological exchange. These three authoritative reviews were marked by great clarity and a true genius for exposition. They were used by many young geneticists as a basis for learning to read scientific German.

In 1932, Stern attended the Sixth International Congress of Genetics, held at Cornell University. It was a personal triumph for him, for his great contributions to genetics had already made him a world leader, at the age of 29 years! During the same summer he was married to an American girl, Evelyn Sommerfield. Alarmed by the ominous anti-Semitism of the Nazi party, a few months after it had grasped supreme political power in Germany, Stern made arrangements to stay at the California Institute of Technology for a half-year, with the transplanted Morgan group of Drosophila geneticists. He was never to return to live in the land of his birth. A temporary appointment at the University of Rochester kept him afloat for a couple of years, after which he obtained a regular academic appointment there. By 1941 he had become a full professor, and for six years was chairman of the department of zoology.

At the University of Rochester Curt Stern did some of his most famous work, including a demonstration that crossing-over can occur in somatic cells (1936). He performed transplantation studies that demonstrated that the development of spirally coiled Drosophila testes, instead of straight ones, depends upon whether the testes become attached to the sperm ducts during the course of development (1941). He proved that the effect of a gene may be altered by its position, by its neighbor genes, in the chromosome -- position effect -- and he also discovered isoalleles, that is, genes which produce the same morphological effect but differ from other alleles at the same locus in respect to dominance, mutation rate, or other physiological characteristics (1943). During wartime, he carried out a classified study, not published until after the War, of the action of very low doses of X-rays or gamma radiation in producing mutations, and demonstrated that even doses of 25 or 50 roentgens do in fact produce mutations at a rate predicted by extrapolating linearly downward from the frequencies found at doses of 1,000 roentgens or more. This study had a vast practical significance in later debates about the danger of low doses of high-energy radiation received by human populations, as well as other species, from fallout after nuclear tests; and it provided strong support for those who were alarmed at the large cumulative amounts of radiation received by persons from the use of X-rays in medical and dental diagnoses. As a consequence of this investigation, Stern was chosen to serve on the Advisory Committee for Biology and Medicine of the Atomic Energy Commission from 1950 to 1955.

In teaching genetics to premedical students at Rochester, Stern was impelled by these studies, as well as the express interest of the students, to place an increasing emphasis on human genetics. At the time of his transfer to a professorship at the University of California, in 1947, he became interested in the population dynamics of the Rh blood group incompatibility between Rh-negative mothers and their Rh-positive fetuses. He was also greatly interested in the possibility of finding genes in the human Y-chromosome, as a parallel to the presence of the bobbed alleles in the Y-chromosome of the fruitfly. He began work on a greatly needed modern textbook for students of human genetics, and with its publication in 1947 as Principles of Human Genetics and its translation into several other languages he became, in general opinion, the foremost authority in the world on human genetics. A very great deal of the correspondence in the Curt Stern Papers relates to inquiries from readers of the book, or to Stern's efforts to correct minor errors and to incorporate new, important discoveries in the second and third editions of the textbook. As a well-known authority in the field, he was in great demand for guest lectures, and innumerable personal questions about the inheritance of particular conditions affecting health or personality were directed to him. More and more honors were accorded him in these last two decades of his life.

Curt Stern was an exemplary teacher and writer, and a man of deep human feeling and probity. He organized a film course in genetics for the American Institute of Biological Sciences in the early 1960s, and was himself the lecturer in a dozen of them. He participated in many workshops dealing with genetic counseling and took the time to answer the volumes of letters appealing to his knowledge in such matters. He trained a number of able students, among them James V. Neel, who himself became a leader in research in human genetics. Foreign students would have flocked to him at Berkeley, but except for those who wanted to work with Drosophila, he had to turn them away because he held his post in a department of zoology rather than in genetics, where he might have accepted students in human genetics and could have obtained the resources to support them. Perhaps he was glad of this, for he remained in his research interests primarily a devotee of Drosophila. He also became interested in the history of genetics, and in particular in the rediscovery of Mendel's work. In his book on The Origin of Genetics, written with Eva Sherwood, he emphasized the minor role of Erich Tschermak in the rediscovery. His late public lectures and essays became more and more philosophical, in the light of his own personal experiences. The titles are indicative: as to scientific research, "The Journey, not the Goal"; as to human genetics, "Genes and People": as to the relation of genetics to the other sciences and to human welfare, "The Domain of Genetics." His personal modesty tempered the scientific rigor of his mind. His influence, among those of his generation-the last of the great Drosophila geneticists of the pre-World War II period-was unparallelled.

There is a certain irony in the fact that his last years were increasingly clouded by the degenerative processes of Parkinson's disease, one of the human ailments that medical genetics is still striving to understand and alleviate.

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