Who discovered transformation in bacteria?

The discovery of transformation in bacteria is attributed to Frederick Griffith, who conducted a pivotal experiment in 1928. Griffith worked with two strains of Streptococcus pneumoniae: a virulent strain that caused pneumonia and a non-virulent strain that did not. When he injected mice with the live non-virulent strain, they remained healthy; however, when he injected them with the heat-killed virulent strain, the mice also survived. The groundbreaking result came when he mixed the heat-killed virulent strain with the live non-virulent strain, and the mice developed pneumonia and died.

Griffith concluded that some "transforming principle" from the heat-killed virulent bacteria had converted the non-virulent bacteria into a virulent form. This experiment laid the foundational understanding of genetic transformation, establishing that traits could be transferred between bacteria, ultimately leading to the discovery of DNA as the carrier of genetic information.

The other named individuals, while critical in their own fields, are not associated with the discovery of transformation in bacteria. Charles Darwin is known for his theory of evolution; Avery MacLeod later identified DNA as the transforming principle discovered by Griffith; and Erwin Chargaff is recognized for Chargaff's rules regarding DNA