Final answer:
Frederick Griffith identified the process of bacterial transformation when he observed that a 'transforming principle' from heat-killed pathogenic bacteria could turn nonpathogenic bacteria into a virulent form, demonstrating horizontal gene transfer in bacteria.
Step-by-step explanation:
Frederick Griffith's Novel Findings
Frederick Griffith's experiments in 1928 discovered a remarkable phenomenon known as transformation. He worked with Streptococcus pneumoniae, using two strains, the nonpathogenic rough (R) strain, and the pathogenic smooth (S) strain. Injecting mice with the S strain resulted in the mice's death, whereas the R strain did not kill the mice. \
However, when Griffith mixed heat-killed S strain with live R strain and injected the mixture into mice, the mice died. Upon examining the bacteria recovered from the mice, Griffith found that the non-virulent R strain had been transformed into a virulent S strain. Griffith deduced that the dead S strain had passed a 'transforming principle' to the live R strain, altering it to become pathogenic. This groundbreaking discovery paved the way for understanding that DNA is the material responsible for heredity.