Which scientists first gave experimental evidence that DNA is the genetic material?
(1) Avery, MacLeod , and McCarty who repeated the transformation experiments of Griffith, and chemically characterized the transforming principle.
(2) Garrod, who postulated that Alcaptonuria, or black urine disease, was due to a defective enzyme.
(3) Beadle and Tatum, who used a mutational and biochemical analysis of the bread mold Neurospora to extablish a direct link between genes and enzymes.
(4) Meselson and Stahl who showed that DNA is replicated semiconservatively.