There is an illuminated moment in the development of a child when she grasps the recursiveness of language: just as thoughts can be used to generate words, she realizes, words can be used to generate thoughts. Recombinant DNA had made the language of genetics recursive. Biologists had spent decades trying to interrogate the nature of the gene—but now it was the gene that could be used to interrogate biology. We had graduated, in short, from thinking about genes, to thinking in genes.
