I've always felt that the three things that came together to create the modern period of molecular biology were, first of all, Sanger's proof that proteins had a chemical structure, which no one believed – everybody thought they were statistical polymers, or just globs. Seymour Benzer's work on the fine structure of the gene, and of course the Watson and Crick hypothesis, right. But the genetic functionality of Seymour really mapped onto the gene. It gave us a way of analysing DNA. And of course what Sanger had done was of course the functional mapping. And, you see, all of that was put together by Francis in a much more important paper which… much more important than the DNA, which is what was called the Sequence Hypothesis. Nobody believed; see, everybody knew that enzymes were functional things and they had a complex structure. And everybody knew that they'd have to… how the polypeptide chain was determined. And then people actually thought there were separate genes for folding of proteins, and there was separate machinery to do this. And Francis's real, basic simplification was that there were two sequences: a one-dimensional sequence on the nucleic acid which specified a one-dimensional sequence of amino acids in a polypeptide chain, and that one-dimensional sequence of amino acids in the polypeptide chain in turn specified how the protein folded up. And that's the fundamental thing. And that really crystallised all the problems, all the issues, into the following questions: how does the DNA structure map onto the amino acid sequence? That is, what is the genetic code? Of course there's a subsidiary question, which is what is the mechanism of protein synthesis? But we could formulate an abstract question: what is the nature of the genetic code? And of course what the theoreticians wanted to do is solve it without hands. And the other question was to understand the folding of these… of these polypeptide chains into proteins. And that is… that… that lays the… the groundwork for molecular biology.