In 1944, they published their landmark paper demonstrating that DNA was the transforming principle. They built upon the work of Frederick Griffith who, in 1928, had shown that a substance from heat-killed S bacteria could transform live R bacteria into S bacteria.
Avery and his colleagues carefully purified the substance and showed that:
* DNA was the only substance capable of transforming R bacteria into S bacteria.
* Proteins, RNA, and other cellular components were not responsible for the transformation.
This discovery was a groundbreaking finding in the history of genetics and helped establish DNA as the carrier of genetic information.
