Edward Simon showed that the results of this experiment held in HeLa cells. When reviewing the manuscript that ultimately published this experiment's 
Edward Simon showed that the results of this experiment held in HeLa cells. When reviewing the manuscript that ultimately published this experiment's results, John Cairns suggested a reason why its results with salmon sperm were different. Along with Vinograd, the experimenters had the year before perfected a way of using cesium chloride to establish a density gradient during centrifugation. This pulse-chase experiment disproved Max Delbrück's ideas about the "unwinding problem." It grew E. coli in nitrogen-15 labeled media for several generations, then moved it to a nitrogen-14 medium and looked at the density of DNA in further generations. For 10 points, what doubly-eponymous experiment confirmed the semiconservative nature of DNA replication?
Edward Simon showed that the results of this experiment held in HeLa cells.
Meselson-Stahl experiment