FOXP2 in focus: what can genes tell us about speech and language?

https://doi.org/10.1016/S1364-6613(03)00104-9Get rights and content

Abstract

The human capacity for acquiring speech and language must derive, at least in part, from the genome. In 2001, a study described the first case of a gene, FOXP2, which is thought to be implicated in our ability to acquire spoken language. In the present article, we discuss how this gene was discovered, what it might do, how it relates to other genes, and what it could tell us about the nature of speech and language development. We explain how FOXP2 could, without being specific to the brain or to our own species, still provide an invaluable entry-point into understanding the genetic cascades and neural pathways that contribute to our capacity for speech and language.

Section snippets

A gene mutated in a speech and language disorder

A 2001 study identified the first case of a gene that may be implicated in our abilities for acquiring spoken language [10]. In humans, mutation of this gene, which has the technical name of ‘FOXP2’ (see Box 1) results in a severe developmental disorder that significantly disrupts speech and language skills. The discovery of a link between FOXP2 and spoken language owes something to recent innovations in the field of molecular genetics [11], but was largely dependent on an opportune finding of

FOXP2 function–lessons from developmental biology

Before we can properly address these and other related questions, we must gain some idea of the normal function of FOXP2. Fortunately, we can already make some educated guesses, by comparing the sequence of the gene to that of other genes that have been studied for several years and are thus better understood. On the basis of these comparisons, the FOXP2 gene belongs to a group of genes that make proteins containing forkhead-box (FOX) domains [22] (Box 3). FOX proteins are themselves just one

Building brains…and lungs, guts and hearts

FOXP2 is expressed in restricted parts of the developing brain and might participate in generating neural substrates involved in acquisition of spoken language. But FOXP2 is also expressed in defined regions of other tissues during embryo development, including the lung, the gut and the heart [26], as well as in several tissues of the adult organism [10]. Again, this has parallels in what we already know about other transcription factors, many of which have multiple differing jobs, sometimes at

Evolving FOXP2

Just as FOXP2 is not unique to the brain, it is not unique to Homo sapiens. Mice, for example, have a version of the gene with a nucleotide coding sequence that is 93.5% identical to the human version [27], and yet (except in the world of cartoons and children's films) no mouse has ever been heard to speak. Does the observation that FOXP2 is present in a similar form in a broad range of mammalian species imply that it is not involved in speech and language after all? Not at all. If the rest of

Uncovering neural pathways

FOXP2 cannot be called ‘the gene for speech’ or ‘the gene for language’. It is just one element of a complex pathway involving multiple genes, and it is too early to tell whether its role within that pathway is special. Furthermore, FOXP2 appears to be normal in common forms of developmental language disorder, and these seldom involve the kinds of oromotor deficits observed in the KE family [35]. Nonetheless, the gene can provide a valuable entry-point into the relevant neural pathway (or

Acknowledgements

G.F.M. was supported by the NIH, the HFSP, the MacArthur Foundation and the Center for Advanced Study in Behavioral Sciences. S.E.F. is a Royal Society Research Fellow.

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