McCarty, Maclyn

born June 9, 1911, South Bend, Ind., U.S.

died Jan. 2, 2005, New York, N.Y.

U.S. biologist.

He received an M.D. (1937) at Johns Hopkins School of Medicine. With Oswald Avery and Colin M. MacLeod he provided the first experimental evidence that the genetic material of living cells is composed of DNA. In their classic experiments (1944), the introduction of certain material from one type of pneumococcus bacteria into another type transformed the receiving bacteria into the type from which the material had been taken. The substance responsible for the change was DNA.

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▪ 2006

      American microbiologist and physician (b. June 9, 1911, South Bend, Ind.—d. Jan. 2, 2005, New York, N.Y.), together with colleagues Oswald Avery and Colin MacLeod, provided the first evidence that genes are composed of DNA, a discovery that made possible the later development of molecular biology and genetic engineering. McCarty and his colleagues obtained their evidence from experiments, published in 1944, in which a “transforming principle” (genetic material) extracted from one type of pneumococcal bacteria and mixed with a second type would impart characteristics of the first to the second type. As a skilled biochemist, McCarty succeeded in purifying and identifying the extract. McCarty graduated (1933) from Stanford University with a degree in biochemistry, and he received an M.D. degree (1937) from Johns Hopkins University School of Medicine, Baltimore, Md. He went to work in Avery's laboratory at the Rockefeller Institute for Medical Research (now Rockefeller University), New York City, in the early 1940s. In 1946 McCarty was appointed head of the Laboratory of Bacteriology and Immunology at Rockefeller, and he became a leader in research on streptococcus bacteria and their role in producing rheumatic fever. McCarty served as physician in chief (1960–74) at the Rockefeller University Hospital and as vice president (1965–78) of Rockefeller University. In 1994 he received an award for special achievement in medical science from the Lasker Foundation. A memoir, The Transforming Principle, appeared in 1985.

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▪ American biologist

born June 9, 1911, South Bend, Indiana, U.S.

died January 2, 2005, New York, New York

      American biologist who, with Oswald Avery (Avery, Oswald) and Colin M. MacLeod, provided the first experimental evidence that the genetic material of living cells is composed of deoxyribonucleic acid ( DNA).

      McCarty attended Stanford University (B.S., 1933) and Johns Hopkins School of Medicine (M.D., 1937) before joining William S. Tillett at New York University in 1940. Tillett not only introduced McCarty to the study of pneumococcic bacteria but also arranged for him to work with Avery in his laboratory at the Rockefeller Institute (now Rockefeller University) in New York City. McCarty became a member of the institute in 1950 and later served as its vice president (1965–78). From 1960 to 1974 he was physician in chief at the school's hospital. He also chaired New York City's Public Health Research Institute (1985–92).

      McCarty's classic experiments with Avery and MacLeod, published in 1944, involved the transformation of certain types of pneumococcus into distinctly different types. The transformation occurred when cell-free material, extracted from one type of bacterium encased in smooth capsules in the living state, was mixed with living bacteria of a second type lacking capsules. The second type would then produce a capsule characteristic of the first type, with which it had been mixed. The results of this research indicated that the substance responsible for the change was DNA. The three men's work gave rise to the field of molecular biology.

      Among McCarty's numerous honours was an Albert Lasker Award for special achievement (1994).

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