What is the Griffith experiment?

The Griffith experiment, conducted by Frederick Griffith in 1928, was a pivotal study in microbiology and genetics. It was the first experiment that suggested bacteria could transfer genetic information via a process known as transformation. 

Griffith’s aim in conducting the experiment was to investigate different strains of Streptococcus pneumoniae, a pneumonia-causing bacterium that showed two growth patterns. As part of the experiment Griffith injected Smooth and Rough strains of the bacteria into mice. Accidently, he discovered that when he injected mice with a combination of heat-killed pathogenic bacteria and live non-pathogenic bacteria, the live bacteria became pathogenic and caused diseases. This indicated that some “transforming principle” from the dead bacteria was transferring genetic material to the live bacteria, which could then express new traits.