Griffith's Discovery & DNA: Understanding Bacterial Transformation

In 1944, Oswald Avery, Colin MacLeod, and Maclyn McCarty demonstrated that DNA is the molecule responsible for transformations in bacteria. They built on the work of Frederick Griffith, who had earlier shown that a heat-killed strain of bacteria could transfer genetic material to a live strain, transforming the live strain's genotype and phenotype. Avery, MacLeod, and McCarty showed that the transforming substance was DNA and that it was capable of carrying the genetic information necessary to transform one genotype into another. This discovery was a major breakthrough in genetics and laid the foundation for understanding the role of DNA in heredity and gene expression.