DNA is genetic material demonstrated by Avery-MacLeod-McCarty Experiment

February, 1944. Oswald Avery, Colin MacLeod and Maclyn McCarty publish a report in the February issue of the Journal of Experimental Medicine detailing their work over the previous decade. The results suggest that DNA, not protein as was commonly believed, is the hereditary material for bacteria, and the cause of bacterial transformation.

The report, entitled "Studies on the Chemical Nature of the Substance Inducing Transformation of Pneumococcal Types: Induction of Transformation by a Deoxyribonucleic Acid Fraction Isolated from Pnuemococcos Type III," showed that injecting mice with dead streptococcus pnuemoniae bacteria of a virulent strain along with a living non-virulent type of the same bacteria resulted in a severe, often fatal, infection. This infection was of the virulent type, despite its state at the time of injection.

This was the first suggestion of the importance of DNA. The molecule would not be conclusively recognized as the means of inheritance until the late 1950s.

-Amy Dyrbye

  • Avery, O. et al. (1944). Studies on the Chemical Nature of the Substance Inducing Transformation of the Pneumococcal Types: Induction of Transformation by a Deoxyribonucleic Acid Fraction Isolated from Pnuemococcos Type III. Journal of Experimental Medicine, 79, 137-158.

  • Deichmann, U. (2004). Early responses to Avery et al.’s paper on DNA as hereditary material. Historical Studies in the Physical and Biological Sciences, 34, 207-232.

DNA is genetic material demonstrated by Avery-MacLeod-McCarty Experiment

February, 1944. Oswald Avery, Colin MacLeod and Maclyn McCarty publish a report in the February issue of the Journal of Experimental Medicine detailing their work over the previous decade. The results suggest that DNA, not protein as was commonly believed, is the hereditary material for bacteria, and the cause of bacterial transformation.

The report, entitled "Studies on the Chemical Nature of the Substance Inducing Transformation of Pneumococcal Types: Induction of Transformation by a Deoxyribonucleic Acid Fraction Isolated from Pnuemococcos Type III," showed that injecting mice with dead streptococcus pnuemoniae bacteria of a virulent strain along with a living non-virulent type of the same bacteria resulted in a severe, often fatal, infection. This infection was of the virulent type, despite its state at the time of injection.

This was the first suggestion of the importance of DNA. The molecule would not be conclusively recognized as the means of inheritance until the late 1950s.

-Amy Dyrbye

  • Avery, O. et al. (1944). Studies on the Chemical Nature of the Substance Inducing Transformation of the Pneumococcal Types: Induction of Transformation by a Deoxyribonucleic Acid Fraction Isolated from Pnuemococcos Type III. Journal of Experimental Medicine, 79, 137-158.

  • Deichmann, U. (2004). Early responses to Avery et al.’s paper on DNA as hereditary material. Historical Studies in the Physical and Biological Sciences, 34, 207-232.