Who provided key evidence for the semiconservative model of DNA replication?

The semiconservative model of DNA replication suggests that during DNA replication, each daughter DNA molecule consists of one old strand and one newly synthesized strand. The key evidence for this model was provided by Meselson and Stahl through their landmark experiment in the 1950s.

In their study, they used isotopes of nitrogen to label the DNA in bacterial cells. By growing E. coli in a medium containing a heavy nitrogen isotope, they ensured that the DNA became heavy. They then transferred these bacteria to a medium with a lighter nitrogen isotope and allowed them to replicate. By analyzing the density of the DNA after multiple rounds of replication using density gradient centrifugation, they were able to observe that after one round of replication, the DNA consisted of hybrid strands, and after two rounds, there were both hybrid and light strands. This pattern was consistent with the semiconservative model, as it demonstrated that each new DNA molecule contained one original and one new strand.

The other options are mainly associated with different findings in molecular biology. Watson and Crick are credited for elucidating the double helix structure of DNA, while Avery and Chase are known for contributions to the understanding of genetic material. Hershey and Chase are famous for their experiments that confirmed DNA as