Representation in the genome

Abstract

Many biologists, and others, use representational talk to describe a range of genomic phenomena: ‘transcription’, ‘translation’, ‘the genetic code’ etc. How seriously we should take this depends on our account of representation. ‘Teleosemantics’ is an account that bases representational content on the functions of biological systems (‘devices’) that produce and consume physical tokens so as to communicate with one another and deal successfully with the world. On this view, many biological systems other than human beings display representational capacities. In particular, molecular genes within a cell, working with other cellular machinery, send messages to the ribosomes about what proteins to synthesise, how much and when. These messages are crucial to nearly all biological processes and, on a teleosemantic view, genuinely represent both the proteins that are to be synthesised and the environmental conditions with which those proteins are supposed to deal. It is tempting to think that a gene could also represent a trait —e.g. that the allele for yellow seeds in peas represents yellow seeds. The trouble is that there is no single consumer device to which the gene is sending a message. Most representation in the genome is fairly rudimentary but in some cases the genome displays more sophisticated capacities. Circadian clocks have evolved to represent future states of affairs and many viruses and bacteria practice genetic deception on host organisms. I also explore two attributes that are fundamental to the genome’s representational power: the compositionality of the parts that make it up and the arbitrariness of the genetic code that underpins the expression of molecular genes. Finally, I consider three ways of disputing the teleosemantic story about representation in the genome. First, are we obliged to say that representation is generated by functions deriving from inheritance systems other than the genome, hormonal inheritance systems, environmental niche construction, symbiosis etc? This is mostly an empirical matter and, in the current state of knowledge, the answer is largely in the negative. Second, is representational talk about the genome somehow second-rate: just a metaphor or an analogy or a useful model? In all three cases, my answer is ‘No’. Such worries boil down to worries about the teleosemantic story itself: they are not independent reasons to deny that the genome has representational capacities. Third, does according representational status to various nucleic acid structures do genuine conceptual work? Yes, it does. It improves the coherence of our theory of representation, presents a range of opportunities for further work, and has important implications for the way we see the kind of representation that human beings do.