Biology / Unit 6 Bio 1211 short lesson, about 20 seconds
Meselson and Stahl's Semiconservative-Replication Experiment (1958)
Captions available
The idea
Matthew Meselson and Franklin Stahl showed in 1958 that DNA replicates semiconservatively: each new helix keeps one original strand and one new strand.
In practice
E. coli grown in heavy nitrogen, then shifted to light nitrogen, produced DNA of intermediate density after one replication round.
Where people slip
This result distinguished semiconservative replication from two rival models the experiment tested, not merely an assumed answer.
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