What is transformation? Describe Griffith’s experiment to show transformation? What did he prove from his experiment?
Transformation means a change in the genetic makeup of an individual. Fredrick Griffith conducted a series of experiments on streptococcus pneumoniae. He observed two strains of this bacterium –one forming smooth colonies with capsule (s-type) & the other forming rough colonies without capsule (R-type). When live s-type cells are injected into mice, they produce pneumonia & mice die. When liveR-type cells are injected into mice, the disease was not produced and did not appear. When heat-killed S-type cells were injected into mice, the disease did not appear. When heat-killed S-type cells were mixed with live R-cells & injected into mice, the mice died. He concluded that R-strain bacteria had somehow been transformed by heat-killed S-strain bacteria which must be due to the transfer of genetic material.
