Who explained the ‘transforming principle’ in an organism? How did the scientist perform the experiment to explain this principle?

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answered May 13, 2019 by Divyanshi (25.9k points)
selected Jul 16, 2019 by subrita

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Frederick Griffith (1928) conducted experiments with Streptococcus pneumoniae (bacterium causing pneumonia).

He observed two strains of this bacterium—one forming smooth shiny colonies (S-type) with capsule, while other forming rough colonies (R-type) without capsule.
When live S-type cells were injected into mice, they died due to pneumonia. When live R-type cells were injected into mice, they survived.
When heat-killed S-type cells were injected into mice, they survived and there were no symptoms of pneumonia.
When heat-killed S-type cells were mixed with live R-type cells and injected into mice, they died due to unexpected symptoms of pneumonia. He concluded that heat-killed S-type bacteria caused a transformation of the R-type bacteria into S-type bacteria.