The phenomenon of transformation was discovered by Griffith in which bacteria? (IGKV CET Horti. 2017)

✅Explanation: The phenomenon of bacterial transformation, where genetic material is transferred from one bacterium to another, was discovered by Frederick Griffith in 1928. He used two strains of Diplococcus pneumoniae (now known as Streptococcus pneumoniae):
-S strain (Smooth): Virulent (disease-causing) due to a polysaccharide capsule that protects it from the host's immune system.
-R strain (Rough): Non-virulent, lacking the capsule and unable to cause disease.

• Griffith's Experiment:
-He injected mice with live S strain bacteria – the mice died.
-He injected mice with live R strain bacteria – the mice survived.
-He injected mice with heat-killed S strain bacteria (inactive) – the mice survived.
-Crucially, he injected mice with a mixture of heat-killed S strain and live R strain bacteria – the mice died, and Griffith also recovered live S strain bacteria from these dead mice.