There are 3 major experiments which proves DNA as a genetic material from that we will see transformation experiment.
- Transformation experiment
- Macloed, Avery, MaCarty: Nature of transforming factor is DNA.
- Harshey and Chase experiment.
Transformation experiment
This experiment was performed by Freidrick Griffith in 1928. The experiment was performed on bacterium Streptococcus (Diplococcus) pneumoniae. He selected 2 strains of bacteria Streptococcus (Diplococcus) pneumoniae which are rough and smooth strain. Rough strain was non virulent and smooth strain was virulent.
- Griffith 1st select a rough strain (non virulent) and injected into a mice, that mice remains heathy and no disease concluded.
- 2ndly he selected a smooth strain (Virulent) and injected into a mice, the mice develops a disease and died.
- Under 3rd condition he selected heat killed smooth strain and injected into a mice but this time mice survives.
- Next time he selected rough strain + heat killed smooth strain and injected into a mice and the affected mouse dies.
From the above experiment Griffith concluded that there must be something transforming factor which was received by this live rough cells and this cells get transformed into smooth strain.