DNA Papers #8: Maclyn McCarty and Oswald Avery

In Episode 8 of the DNA papers, we discuss the papers that directly followed up the discovery of the 1944 paper from episode 7. These papers, which have received little attention in histories of DNA, describe the purification and experimental use of an enzyme, desoxyribonuclease, or DNase, which specifically destroys DNA. By showing how the transforming principle is specifically inactivated by this enzyme alone and not by RNA- or protein-degrading enzymes- the DNase experiments left “little doubt” that DNA is the chemical substance responsible for the transformation of bacterial types. Papers discussed include: McCarty, Maclyn. 1946. “Purification and Properties of Desoxyribonuclease Isolated from Beef Pancreas.” The Journal of General Physiology 29 (3): 123–39. McCarty, Maclyn, and O.T. Avery. 1946. “Studies on the Chemical Nature of the Substance Inducing Transformation of Pneumococcal Types. II. Effect of Desoxyribonuclease on the Biological Activity of the Transforming Substance.” Journal of Experimental Medicine 83: 89–96. Returning to the podcast series to share their thoughts on the place of these experiments in DNA history are: Mark Lorch, University of Hull Geoffrey Montgomery, Independent Science Writer Michel Morange, École Normale Supérieure Jan Witkowski, Cold Spring Harbor Laboratory Additional resources on this topic are available at https://www.chstm.org/video/144 Recorded on June 22, 2023.

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A new public events series from the Consortium for History of Science, Technology and Medicine brings historical perspective to contemporary issues and concerns. In the public forums, historians and other specialists speak about culturally relevant topics in front of a live audience at Consortium member institutions. Forum subjects range from medical consumerism to public trust in science and technology. Videos of these events are also available at chstm.org. In podcast episodes, authors of new books in the history of science, technology, and medicine respond to questions from readers with a wide variety of backgrounds and expertise. These conversations illuminate the utility and relevance of the past in light of current events.