Oswald Avery and others have continued Griffth’s transforming principle to prove DNA as genetic material . Substantiate.

Explanation

Griffith-Experiments –rough and smooth strains of Streptococcus pneumonia
S-strain-injected to mice-mice die R-strain-injected to mice-mice live Heat killed S-strain injected to mice did not kill them Heat killed S-strain mixed with R-strain injected to mice, they died R strain of bacteria transformed by heat killed S-strain, become virulent but biochemical nature of genetic material not defined -some transforming principle transferred from heat killed S strain.
Oswald Avery and others worked to determine biochemical nature of transforming principle. Proteins, DNA, RNA from heat killed S cells-purified-discovered that DNA alone from S bacteria cells caused R bacteria to become transformed. Protein digesting proteases, RNA digesting RNases did not cause transformation. Transforming substance was not protein or RNA. DNase did inhibit transformation. Suggested that DNA caused transformation and DNA is the hereditary material