The grammar of genes: How the genetic code resembles the linguistic code (review)

Research on the origin of human language is a heavily mined area. Since most of us like the idea of our being unique, whoever attributes higher mental capacities to hominids other than humans runs the risk of committing a sacrilege. This is why we intuitively like, for example, the hypothesis of a big bang mutation endowing humans with language. Nevertheless, the hopes to discover a language gene—after a 1991 publication on a family with an inherited Specific Language Impairment there was much ado about such a putative gene—have dwindled in recent years, since the candidate eventually turned out to be a very old and very conserved transcription factor of the forkhead box class (FOXP2) expressed not only in the brain, but also in the lung, the small intestine, and the heart of men, apes, mice, birds, fish, alligators, and so on, affecting in humans above all motor control. In such a context, this book by López-García is not without risk, but highly welcome.

Before expounding his ideas of the origin of language, LG reviews the proposals made up to now. Basically, there are two types: (i) language is based on the evolution of the brain ('Inside out', 15–25), and (ii) language is based on adaptation and social needs ('Outside in', 27–43). In the first line of thinking we get acquainted with Charles Darwin, with the concept of exaptation (i.e. taking advantage, challenged by a specific context, of a new stage of evolution), and, last but not least, with the big mutation hypothesis. The 'outside in' hypothesis highlights motor control and gesture or pantomime (Giacomo Rizzolatti's mirror neurons), thus linking our language faculty with a largely cultural context.

Ch. 4 ('Formal inheritance', 43–61) gives us a first glimpse of the ideas favored by LG: he familiarizes us with three landmarks in the history of biology: Goethe, his French contemporary Geoffroy de Saint Hilaire, and, later, D'Arcy Thompson. All three were, in a certain sense, heretics against what is now established as the 'pure doctrine' of Darwin: they brought to the fore the importance of the shape taken by three-dimensional bodies. De Saint Hilaire, while comparing the skeletons of a large variety of animals, discovered that all share the building principle of an anterior-posterior axis in their body plan. As we have known since the late 1980s, this discovery has a genetic basis: there is a series of so-called homeobox genes, ranking on top of a hierarchy of genes responsible for the adequate layout and patterning of a growing body. In most cases they define an anterior-posterior axis, a top-down axis, and a left-to-right axis: 'The hypothesis I am formulating in this book is that the form of I[nternal]-language corresponds to the form of the genetic code as such' (67).

In order to substantiate his claim, LG distinguishes three concepts of grammar: (i) cognitive and conceptual grammars interested in the projection of the outside world onto linguistic forms, (ii) functional grammars based on the use of language, and (iii) grammar as formal syntax manifested above all in the minimalist program reducing syntax to mainly three fundamental operations: select, merge (which implies hierarchy), and move. While (i) and (ii) are compatible with the concept of adaptation, (iii) 'lacks any explanation relative to the external world' (67). This raises the question: when elementary principles shared by all human languages cannot have an evolutional or adaptive background, where do they come from?

Addressing this question, LG first refers to the central metaphor biologists use when describing DNA and its working principles: language in its written alphabetic form. The four nucleotide bases are the 'letters of the genetic alphabet', RNA-polymerase is 'reading' DNA-sequences that are 'transcribed', then 'proof-read', the resulting 'copy' being subject to further 'editing' before it is 'translated' into a polypeptide. The whole process...