How did Frederick Griffith demonstrate that DNA not protein could cause changes in a cell's genotype?
Frederick Griffith demonstrated that DNA, not protein, could cause changes in a cell's genotype through his experiment with Streptococcus pneumoniae bacteria. He observed that injecting mice with a mixture of non-virulent and heat-killed virulent strains resulted in the transformation of the non-virulent bacteria into a virulent form. This indicated that the genetic material responsible for the transformation was DNA.