Chapter 16: The Molecular Basis of Inheritance 16.1: DNA is the genetic material The Search for the Genetic Material: Scientific Inquiry Evidence that DNA Can Transform Bacteria Fredrick Griffith studied a bacterium that causes pneumonia in mammals killed pathogenic bacteria with heat and then mixed with living bacteria of nonpathogenic some of the living became pathogenic transformation = change in genotype and phenotype due to the assimilation of external DNA by a cell Oswald Avery broke open bacterium?s proteins, DNA, and RNA transformation only occurred with DNA Evidence that Viral DNA Can Program Cells bacteriophages - viruses that infect bacteria Hershey and Chase used radioactive sulfur and phosphorus to trace fates of protein and DNA