The maize geneticist Barbara McClintock (1902-1992) is credited with the discovery of "jumping genes," that is chromosomal "crossing over" and translocation. She received the Nobel Prize in Physiology or Medicine in 1983. The collection is organized into six series: I. Correspondence, 1931-1991; II. Subject files, 1938-1989; III. Works by McClintock, 1944-1989; IV. Works by others, 1927-1991; V. Research notes, notebooks, and card files, 1930s-1990s ; VI. Photographs, 1928-1991.

A biochemist at Columbia University, Erwin Chargaff discovered the base-pairing regularities or "complementarity relationships" of nucleic acids that provided one of the key steps in developing a structural model for DNA. During his long career, Chargaff is credited with conclusively falsifying the tetranucleotide hypothesis; demonstrating the existence of a large number of DNA species; and creating the first descriptions of hypochromicity, hyperchromicity, and the denaturation of a DNA. In addition, Chargaff conducted important research on blood coagulation, lipids and lipoproteins, the metabolism of amino acids and inositol, and the biosynthesis of phosphotransferases. He retired to emeritus status in 1974 and remained active in research almost to the time of his death in June 2002. The Chargaff Papers are organized into ten series: I. Correspondence, 1931-1992; Ia. Correspondence, 1949-2002; IIa. Grants, 1930-1982; IIb. Subject Files, 1940-1984; IIc. Subject Files, 1946-2002; III. Works by Chargaff, 1929-1989; IIIa. Works by Chargaff, 1923-2002; IIIb. Reprints, 1977-1999; IV. Works by Others, 1936-1985; IVa. Works by Others, 1976-2002; V. Research Notes and Notebooks, 1929-1951 ; VI. Photographs, 1935-1977; VIa. Photographs, 1928-2002; VII. Audiovisual Materials; VIII. Awards and Certificates, 1958-2001; IX. Lecture Notes, 1942-1985; X. Personal Papers, [1880]-1985.

The correspondence in this collection concerns behavior genetics, evolution, heredity, etc. There is material relating to the congresses of the Permanent International Committee on Genetics, and the IXth (Bellagio, 1953), Xth (Montreal, 1958), and XIth (The Hague, 1963) International Congress of Genetics. There is also correspondence pertaining to the Cold Spring Harbor Symposium on Quantitative Biology (1955), the Mendel Semi-Centennial Symposium (1950), the Soviet geneticists' visit to the U.S. in 1967, and to Anton R. Zhebrak.

This collection of correspondence, reports, and manuscripts concerns Stalker's research in genetics and evolutionary biology, particularly the evolutionary genetics of Drosophila. Most of the letters are scientific, although the usual academic politics in various departments is mentioned. There is also material on the Society for the Study of Evolution (1970).

A geneticist and educator, Philip Macdonald Sheppard was head of the Department of Genetics at the University of Liverpool from 1963-1976. His research centered on polymorphism, mimicry, blood groups, genetic disease, and speciation, using a variety of subjects, including the gastropod Cepaea nemoralis, butterflies, and humans. He may be best remembered for his classic study of industrial melanism in the pepper moth Biston betularia. The Sheppard Papers (1911-1983; bulk dates, 1940-76) contain correspondence, subject files, notes, and manuscripts that document Sheppard's life as a geneticist. The earliest piece in the collection is a lepidopterist's notebook from 1911, possibly J. R. Hobhouse's, however the bulk dates from 1940 to 1976, Sheppard's most productive and influential years. Among other things, these materials document Sheppard's research on the Scarlet Tiger moth, swallowtail butterflies, and ABO blood groups in humans, as well as his position as head of the Department of Genetics at the University of Liverpool.

The geneticist Milislav Demerec emigrated from Yugloslavia in 1919, spending nearly his entire career in the Department of Genetics at Cold Spring Harbor Laboratory. Working initially on the genetics of maize and later on Drosophila virilis, his research interests included radiation and chemical mutagenesis, and during the Second World War, penicillin and the genetics of antibiotic resistance. Demerec served as head of the laboratory at Cold Spring Harbor from 1941 until 1960. The Demerec collection contains the extant professional papers of Milislav Demerec, dating primarily from the time of his arrival at Cold Spring Harbor until his retirement. In addition to his correspondence with colleagues, the collection includes interesting material on the administration of Cold Spring Harbor laboratory during the 1940s and 1950s, data and research notes, material relating to professional organizations (e.g. Genetics Society of America, American Society of Naturalists), a lengthy series of lectures given by Demerec, and a large number of photographs pertaining to Demerec's research, but also to his colleagues and Cold Spring Harbor itself. There is also a Register of visitors to the laboratory (1927-1945) and a Milislav Demerec reprint list.

Sewall Wright ranks among the most influential figures in the field of population genetics during the 20th century, and made important contributions to biostatistics, biometrics, and evolutionary theory. These papers contain much of Wright's professional correspondence, scattered research notes, and drafts of a small number of papers.

The Papers of Curt Stern include extensive correspondence, lectures (1920s-1970s, 1.5 boxes), autobiographical material, articles, zoological course notes, photographs, etc. Stern's various areas of scientific interest are documented in the collection: the chromosome theory of heredity, role of gene mutation and chromosome rearrangements in evolution, action and interaction of genes during individual development, and particularly his contribution to the development of human genetics as a discipline (centered on his popular and influential book, Principles of Human Genetics, 1949, 1960, 1973). Both his career in Germany and the United States is documented in his correspondence. After studying with T. H. Morgan at Columbia University on a Rockefeller Foundation Fellowship (1924-1926), Stern returned to Richard Goldschmidt's lab at the Kaiser-Wilhelm Institute (1926-1932). There is material of note in the collection concerning this period when Stern helped to establish the cytological basis of crossing over. After a short stay at the California Institute of Technology in 1932, Stern's temporary residence in the U. S. became permanent, and his later career at the University of Rochester, 1933-1947 (Chairman, Department of Zoology) and at the University of California, Berkeley, 1947-1970 (there is abundant material on the Department of Zoology) is covered in the collection. There is other material on: American Association for the Advancement of Science Inter-Society Committee on Science Foundation Legislation, 1946-1947; American Society of Human Genetics (Pres., 1957); Atomic Energy Commission (Advisory Committee for Biology and Medicine, 1950-1955); Genetics (journal); Oak Ridge National Laboratory (Advisory Committee for Biology, 1955-1968); and the Rockefeller Foundation. Stern's correspondence with friends and colleagues in Germany, England, and the U. S., during the 1920s-1930s, is of particular note as it documents not only the developments in genetics and the institutional and administrative networks supporting research, but it also offers general comments and observations on science, Germany, and politics. The photographs (2 boxes) include pictures of many prominent geneticists and scientists.