The Genetic Material Is DNA. .. Not Proteins

The accompanying figure depicts aspects of their classic study. Injection of heat-killed virulent S strain was not fatal to the laboratory mice studied. However, coinjection of heat-killed S strain and live nonvirulent R strain killed the mice. The newly created strain continued to be virulent in succeeding generations. Clearly, the genetic factor in the S strain was heat stable and transferred to the R strain. Avery and colleagues purified 

MacLeod, and McCarty submitted a paper in late 1943, and it was published in the Journal of Experimental Medicine in 1944. Although Avery was a highly respected scientist, and bacteriologists and other researchers took note of his paper, his findings remained highly controversial. Many argued that the DNA was, in all likelihood, contaminated with chromosomal protein. Those who have analyzed the slow acceptance 

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