A modest Midwesterner who became one of the most influential geneticists of the first half of the 20th century, William E. Castle spent his career at Harvard and the University of California working on patterns of inheritance in mice, horses, and a variety of other mammalian taxa. An early proponent of Mendelian theory, Castle was director of the Bussey Institution at Harvard for almost thirty years, helping to train a number of important geneticists. The Castle Papers contain one linear foot of correspondence dating primarily from the period after Castle's "retirement" to Berkeley in 1936 until his death in 1962, dealing almost exclusively with his research on horse breeding and the inheritance of coat coloration in horses. Castle's correspondence with his former student L. C. Dunn is an exception, focusing on mouse genetics and ranging to a variety of topics from the conduct of scientific research during the Second World War to Castle's interests in the early history of genetics.

Founded in 1931, the Genetics Society of America works to facilitate communication among scientists with an interest in research and education in genetics and cognate fields. The GSA Records provide information on the history of the Genetics Society of America from the time of its founding in 1931. Included is correspondence between various officers, members, and outside individuals and organizations, files on standing and ad hoc committees, Records concerning accounts and finances, membership data, files relating to annual meetings, local meetings, and international meetings, and information on special commissions or ad hoc groups of the Society. Among the more noteworthy files are those for the Committee on Genetics, Race, and Intelligence, 1974-1975. This note is currently under review for revision.

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.

The James V. Neel Papers document nearly every phase of the career of one of the founders of human population genetics in the United States. Neel was particularly thorough and organized, and retained virtually all of his significant scientific correspondence, committee reports, minutes of meetings, and drafts of manuscripts. The collection also includes data collected during Neel's work among the Xavante, Yanomanö and other indigenous populations. In a career that spanned the period from the late work of Thomas Hunt Morgan and Charles B. Davenport to the contemporary world of molecular genetics and nucleic acids, Neel knew, worked with, and corresponded with many of the most influential 20th century practitioners of genetics. The collection begins in earnest in 1943, after Neel had decided to focus on human genetics. Neel's work with Drosophila and none of his Drosophila manuscripts are found in the collection.