How did transformation contribute to the information known about genetics?
The most important contribution is that it proved that DNA carries genetic information.
Transformation was discovered by Griffith in 1928 when he was researching on the pathogenicity of RII and SIII strains of Diplococcus pneumonea now known Pseudomonas pneumonea.
He discovered that when he injected killed SIII strain bacteria with living RII strain bacteria in mice, they contracted pneumonia although the RII strain bacteria is non pathogenic and the pathogenic SIII strain bacteria where killed.
He figured out that the RII strain bacteria must have taken up DNA from the dead SIII strain bacteria and became pathogenic otherwise there was no other way that this was possible.
Hence, this experiment proved that DNA carries genetic material