Who experimentally confirmed the semi-conservative mode of DNA replication using 15N isotope labeling in E. coli in 1958? (Hard)
Answer and explanation
Correct answer: A. Matthew Meselson and Franklin Stahl
- Step 1: In 1958, density gradient centrifugation with heavy isotope 15N and normal 14N was conducted on replicating E. coli. Step 2. Matthew Meselson and Franklin Stahl demonstrated that hybrid density DNA forms after one generation, proving semi-conservative replication. Answer: Matthew Meselson and Franklin Stahl. Why not the others: Hershey and Chase proved DNA is genetic material using bacteriophages; Watson and Crick solved double helix structure; Avery et al. proved transforming principle is DNA.
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