The ultimate proof for the DNA as a genetic material came from the experiments of
The transduction experiment was done by Alfred Hershey and Martha Chase. They gave unequivocal proof that DNA is the genetic material. They worked with the T2 bacteriophages and E.coli bacteria. They discovered that it was the DNA from bacteriophages that was getting transferred into the bacteria by using a radioisotopic technique.
Biochemical characterisation of the transforming principle was performed by Oswald Avery, Colin MacLeod and Maclyn McCarty. They discovered that protein-digesting enzymes and RNA- digesting enzymes did not affect transformation while digestion with DNase inhibited transformation. This is how they concluded that DNA is the hereditary material.
Gregor Mendel worked on the hybridisation experiment in garden pea (Pisum sativum) where he worked on inheritance patterns of various characters and laid out detailed results.
The bacterial transformation was shown by Frederick Griffith in his experiments on Streptococcus pneumoniae. He took two strains of Streptococcus pneumoniae. They were R (non-virulent) and S (virulent) strains. Transformation is the genetic alteration of a cell that happens as a result of direct uptake and incorporation of genetic material from the surroundings through the cell membrane.