On tritium, DNA, and serendipity.

There is an old saying: "I'd rather be lucky than good, any day." I sometimes (read often) believe that I am living proof of the truth of that adage. In 1955, intermediary metabolism was in its last throes as the "glamour" subject of biology. I finished my Ph.D. work at Ohio State with a dissertation on how Pseudomonas utilized ethylene glycol as a sole carbon source. It was not a brilliant piece of work-it was never published-and I was left feeling very uncertain about my potential as an independent investigator. I had applied to many places for a job (postdoctoral appointments were relatively rare in those days), and one of them was to Brookhaven National Laboratory. I had earlier generated an interest in the killing effects of incorporated radioisotopes, when working on 32p uptake into bacteria, and in my letter to Brookhaven I mentioned this interest. The letter came to the attention of Dr. Walter L. (Pete) Hughes, then head of the Microbiology Division of the Medical Department, who was envisaging the use of tritium as a means of selectively killing growing cells. Thus the letter fortuitously hit the right target. I went to work with Pete in January 1956, just as he prepared the first batch of tritium-labeled thymidine. I had stumbled in on the development of one of the most important tools of modern biology, namely, the use of tritium as a biological tracer in general and, as [3H]thymidine, a specific labeled precursor for DNA. Early in the summer of 1956 Pete informed me that some fellow by the name of Herb Taylor was visiting Phil Woods in the Biology Department and wanted to use [3H]thymidine for a tracer experiment he had devised. We had already begun to grow cells in [3H]thymidine to see if it would kill them, so the [3H]thymidine was available, and Pete agreed