Griffith's experiment

Griffith's experiment is a significant scientific experiment conducted by Frederick Griffith in 1928. It was one of the first experiments suggesting that bacteria could transfer genetic information through a process known as transformation.

Overview

Griffith's experiment involved two strains of Streptococcus pneumoniae bacteria: a virulent strain (S) and a non-virulent strain (R). The S strain was smooth and could cause disease, while the R strain was rough and could not. Griffith found that when he killed the S strain with heat and mixed it with the live R strain, some of the R strain bacteria transformed into the S strain, becoming virulent.

Procedure

Griffith's experiment consisted of four major steps:

1. Griffith injected mice with the live S strain of bacteria. The mice developed pneumonia and died, demonstrating that the S strain was virulent.
2. Griffith injected mice with the live R strain of bacteria. The mice did not develop pneumonia and lived, showing that the R strain was not virulent.
3. Griffith injected mice with the heat-killed S strain of bacteria. The mice did not develop pneumonia and lived, indicating that the heat-killed S strain was not virulent.
4. Griffith injected mice with a mixture of the heat-killed S strain and the live R strain of bacteria. The mice developed pneumonia and died. When Griffith examined the bacteria in the dead mice, he found live S strain bacteria. This suggested that some genetic material from the heat-killed S strain had transformed the live R strain into the S strain.

Significance

Griffith's experiment was significant because it suggested that bacteria could transfer genetic information through a process known as transformation. This was a revolutionary idea at the time and laid the groundwork for future studies on DNA and genetics.

See also

• Avery–MacLeod–McCarty experiment
• Hershey–Chase experiment
• Molecular genetics
• Bacterial transformation

References

Griffith's experiment Resources
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