In 1943 a group of investigators at the Rockefeller Institute, New York City, identified that "transforming principle" as DNA.
It seemed as if some chemical "transforming principle" had transferred from the dead virulent cells into the avirulent cells and changed them.
What it does show is that there was a rational disagreement, at the time, on the question of whether DNA was the transforming principle.
A variant of IBE is also used by Cresto (2008) to reconstruct the experiment by Avery that showed that the transforming principle in pneumococcus is DNA rather than protein.
Griffith's experiment, reported in 1928, identified that some "transforming principle" in pneumococcal bacteria could transform them from one type to another.
After Dawson's departure in 1930, James Alloway took up the attempt to extend Griffith's findings, resulting in the extraction of aqueous solutions of the transforming principle by 1933.
This system provided the first clear suggestion that DNA carries genetic information the Avery MacLeod McCarty experiment when Oswald Avery, along with coworkers Colin MacLeod and Maclyn McCarty, identified DNA as the transforming principle in 1943.
Erwin Chargaff had shown that the base composition of DNA varies by species (contrary to the tetranucleotide hypothesis), and in 1952 Rollin Hotchkiss published his experimental evidence both confirming Chargaff's work and demonstrating the absence of protein in Avery's transforming principle.
For instance, he makes detailed reference to Fred Griffith's discovery of DNA as the "transforming principle" as well as the work of Oswald Avery and colleagues (pp. 68 70).
This was how he discovered, in a traveling library of the US army, the article on the spontaneous nature of bacterial mutations (Luria and Delbrück 1943) and the historic publication by Avery, MacLeod, and McCarthy, who identified the transforming principle as being DNA (Avery et al. 1944).
