who dna is the transforming principle from heat-killed s strain streptococcus pneumoniae that can make the r strain virule
Griffith concluded that the type II-R had been transformed into the lethal III-S strain by a transforming principle that was somehow part of the dead III-S strain bacteria. Today, we know that the transforming principle Griffith observed was the DNA of the III-s strain bacteria. While the bacteria had been killed, the DNA had survived the heating process and was taken up by the II-R strain bacteria. The III-S strain DNA contains the genes that form the protective polysaccharide capsule.