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 bacteriologist from MIT, Salvador E. Luria's work with Max Delbruck on bacteriophage demonstrated that bacterial resistance to certain phages arose through genetic mutations. His later work showed that phages also mutate genetically. He received the Nobel Prize in Physiology or Medicine in 1969 with Max Delbruck and Alfred D. Hershey. The collection is organized into seven series: I. Correspondence, 1938-1992 ; IIa. Subject Files, 1938-1990 ; IIb. Personal Material. 1923-1991 ; III. Works by Luria, 1938-1987 ; IV. Works by Others, 1944-1990 ; V. Research Notes and Notebooks, 1941-1979 ; VI. Course Material, 1931-1991 ; VII. Photographs and Negatives, 1957-1982. Arrangement: Alphabetical by folder title and then chronological within each folder.

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.