Oswald Avery

Oswald Avery was a Canadian-American physician and researcher whose experiments provided the first strong evidence that DNA, rather than protein, is the material that carries hereditary information. Working at the Rockefeller Institute in New York, Avery, together with colleagues Colin MacLeod and Maclyn McCarty, published a landmark 1944 paper building on Frederick Griffith's earlier discovery of bacterial transformation, systematically purifying the transforming substance from pneumococcus bacteria and showing through careful chemical elimination that it was DNA, not protein or other cellular components, that carried the heritable trait between bacterial strains. This finding challenged the prevailing assumption among many biologists of the time that proteins, with their greater chemical complexity, were the more likely carriers of genetic information, and it laid essential groundwork for the identification of DNA's structure by James Watson and Francis Crick less than a decade later. Avery has often been noted as one of the most significant scientists of the twentieth century never to receive a Nobel Prize, a fact frequently attributed to how far his 1944 finding ran ahead of what many contemporaries were prepared to accept.