Explain transformation in bacteria as experimented by Griffith.

Explanation

Transformation :
1. Transfer of DNA from one bacterium to another is called transformation.

2. In 1928 the bacteriologist Frederick Griffith demonstrated transformation in Mice using Diplococcus pneumoniae.
3. Two strains of this bacterium are present. One strain produces smooth colonies and are virulent in nature (S type). In addition another strain produced rough colonies and are avirulent (R type).
4. When S-type of cells were injected into the mouse, the mouse died. When R-type of cells were injected, the mouse survived.
5. When he injected heat killed S-type cells into the mouse the mouse did not die.
6. When the mixture of heat killed S-type cells and R-type cells were injected into the mouse. The mouse died.
7. The a virulent rough strain of Diplococcus had been transformed into S-type cells.
8. The hereditary material of heat killed S-type cells had transformed R-type cell into virulent smooth strains.
9. Thus the phenomenon of changing the character of one strain by transferring the DNA of another strain into the former is called Transformation.