Frederick Griffith is associated with which genetic phenomenon?

• A. Transduction
• B. Transformation in bacteria
• C. Mutation
• D. Conjugation

Answer: (B)

The main concept is bacterial transformation, the process by which a bacterium can take up DNA from its surroundings and change its traits. In Griffith’s experiments with Streptococcus pneumoniae, he showed that when heat-killed virulent (smooth) cells were mixed with living nonvirulent (rough) cells, some living cells became virulent themselves. This indicated that genetic material from the dead cells had been taken up and incorporated, causing a heritable change—what he called the transforming principle. Later work identified this material as DNA. So Griffith is linked to transformation in bacteria. The other options describe different gene-transfer or mutation methods that Griffith did not demonstrate: transduction involves virus-mediated transfer, conjugation involves direct cell-to-cell transfer via pili, and mutation is a change in DNA sequence within an organism.