Griffith’s transformation experiments

Definition

Griffith's transformation experiments were a series of studies conducted by Frederick Griffith in 1928 that demonstrated the phenomenon of bacterial transformation. These experiments provided evidence that genetic material could be transferred between different bacterial strains.

5 Must Know Facts For Your Next Test

1. Griffith worked with two strains of Streptococcus pneumoniae: a virulent S strain and a non-virulent R strain.
2. Mice injected with a mixture of heat-killed S strain and live R strain developed pneumonia and died, indicating that the R strain had been transformed into the virulent S strain.
3. The transforming principle from Griffith's experiments was later identified as DNA by Avery, MacLeod, and McCarty.
4. Griffith's work laid the foundation for understanding that DNA is the molecule responsible for heredity.
5. The experiments illustrated horizontal gene transfer, where genetic information is exchanged between cells without reproduction.

Review Questions

Related terms

Avery-MacLeod-McCarty Experiment: Follow-up research that identified DNA as the transforming principle.

Horizontal Gene Transfer:

Exchange of genetic material between organisms without reproduction.

Streptococcus pneumoniae:

Bacterial species used in Griffith's transformation experiments.