Encyclopedia > Griffiths experiment

  Article Content

Griffith's experiment

Redirected from Griffiths experiment

In 1928, Frederick Griffith conducted an experiment that showed the transformation of living cells by a transforming principle[?], which was later discovered to be DNA.

Griffith used two strains of Pneumococcus[?] (which infects mice), a S (smooth) and a R (rough) strain. The S strain covers itself with a polysaccharide capsule that protects it from the host's immune system, resulting in the death of the host, while the R strain doesn't have that protective capsule and is defeated by the host's immune system.

In his experiment, bacteria from the S strain were killed by heat, and their remains were added to R strain bacteria. It turned out that the formerly harmless R strain now was able to kill its host. It had been transformed into the lethal S strain, obviously by a transforming principle[?] that was somehow part of the dead S strain bacteria.

Today, we know that the DNA of the S strain bacteria had survived the heating process, and was taken up by the R strain bacteria. The S strain DNA contains the genes that form the protective polysaccharide capsule. Equipped with this gene, the former R strain bacteria were now protected from the host's immune system and could kill it.

See also:
genetics -- Hershey-Chase experiment
Oswald Theodore Avery



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
Sakhalin

... of a continent which comprised north Asia, Alaska and Japan, and enjoyed a comparatively warm climate. The Pliocene deposits contain a mollusc fauna more arctic than that ...

 
 
 
This page was created in 41 ms