Griffith's transformation experiment: S and R strains

METHOD

Living S strain

RESULTS

Mouse dies

Living S strain cells found in heart.

Living R strain

Mouse healthy

No bacterial cells found in heart.

Mouse healthy

No bacterial cells found in heart.

Griffith's experiment

Mouse dies

Living S strain cells found in heart.

What did he do?

It was one of the first experiments showing that bacteria can get DNA through a process called transformation. In this experiment, bacteria from the III-S strain were killed by heat, and their remains were added to II-R strain bacteria.

What did he could or couldn't prove?

Griffith found that heat-killed S cells could give these capsule-making instructions to live R cells and those R cells would transform into S cells. And those S cells could cause disease in mice just like normal live S cells do.