Insights into the Genetic Foundations of Human Communication

Abstract

The human capacity to acquire sophisticated language is unmatched in the animal kingdom. Despite the discontinuity in communicative abilities between humans and other primates, language is built on ancient genetic foundations, which are being illuminated by comparative genomics. The genetic architecture of the language faculty is also being uncovered by research into neurodevelopmental disorders that disrupt the normally effortless process of language acquisition. In this article, we discuss the strategies that researchers are using to reveal genetic factors contributing to communicative abilities, and review progress in identifying the relevant genes and genetic variants. The first gene directly implicated in a speech and language disorder was FOXP2. Using this gene as a case study, we illustrate how evidence from genetics, molecular cell biology, animal models and human neuroimaging has converged to build a picture of the role of FOXP2 in neurodevelopment, providing a framework for future endeavors to bridge the gaps between genes, brains and behavior.

Understanding Language from a Genomic Perspective

“…Several common heritable disorders that variously affect aspects of speech, language, and reading are recognized (52). Specific language impairment (SLI) is an unexplained difficulty in spoken language acquisition.…”

“…Over the past two decades, linkage has been used extensively to study these disorders (19,73,105). Some investigations have focused on extended pedigrees, searching for potentially monogenic forms of impairment in a similar manner to the FOXP2 story, although (unlike FOXP2) no high-penetrance etiological variants have yet been pinpointed (52). Most linkage studies have examined cohorts containing many smaller families, demonstrating considerable genetic heterogeneity, with multiple genomic regions involved-at least at the population level, if not within each single family.…”

“…The apparent innateness of mechanisms supporting language acquisition suggests these mechanisms may be grounded in our genome. Indeed, variation in certain linguistic abilities is underpinned by genetic variation between individuals, and developmental disorders affecting aspects of speech and language also have genetic roots (52). The discovery of FOXP2 disruptions causing a rare speech and language disorder illustrated that molecular changes can profoundly affect language development, and subsequent studies of this gene provided a template for connecting genetic variants and crucial human capacities (40).…”

Talking Convergence: Growing Evidence Links FOXP2 and Retinoic Acid in Shaping Speech-Related Motor Circuitry

“…FOXP2 was the first identified monogenic cause of a speech disorder (for review see Graham et al, 2015). However, it remains to be answered how it affects the development of speech related neuronal circuits and what the relevant molecular pathways may be.…”

“…Human patients with FOXP2 mutations show prominent motor learning deficits at the root of their developmental verbal dyspraxia diagnosis, which is reflected in mouse models of Foxp2 loss (for review see Deriziotis and Fisher, 2013; Graham et al, 2015). Interestingly, in mice with dysregulated RA signaling, similar motor learning impairments have been found (for review see Duester, 2013).…”