Abstract

Throughout the history of molecular biology, the primary meaning of biological information has been taken from the image of a word-based linguistic code. I want to argue that the metaphor of such a code does not begin to capture either the variety or the richness of the processes by which nucleotide sequences inform biological processes. Current research demonstrates that nucleotide sequences inform not only development but also heredity and evolution, and they do so in all sorts of ways. Even though they do not exhaust the varieties of biological information employed in these processes, I claim that the power of DNA sequences to inform these processes is richer and perhaps far greater than the conventional understanding of genetic information permits, indeed richer than what any of our images of simple linguistic codes or of senders and receivers permits. Rather than a tape in a Turing machine or a message or signal sent through the generations, DNA is first and foremost a physicochemical structure with a range of potential uses by the physicochemical arsenal of biological cells that is so large as to expose the poverty of our most familiar metaphors. Recognition of this fact leads us to conclude that DNA is both more and less than we thought—more because it carries both symbolic and non-symbolic information and less because accepting that fact undermines its radical distinction from other biological molecules