Introduction to the special section on genomics

Puberty and the Evolution of Developmental Science

In recent decades, theoretical and methodological advances have operated synergistically to advance understanding of puberty and prompt increasingly comprehensive models that engage with the temporal, psychosocial, and biological dimensions of this maturational milepost. This integrative overview discusses these theoretical and methodological advances and their implications for research and intervention to promote human development in the context of changing maturational schedules and massive ongoing social transformations.

Word reading fluency: role of genome-wide single-nucleotide polymorphisms in developmental stability and correlations with print exposure

The genetic effects on individual differences in reading development were examined using genome-wide complex trait analysis (GCTA) in a twin sample. In unrelated individuals (one twin per pair, n = 2,942), the GCTA-based heritability of reading fluency was ~20%-29% at ages 7 and 12. GCTA bivariate results showed that the phenotypic stability of reading fluency from 7 to 12 years (r = 0.69) is largely driven by genetic stability (genetic r = 0.69). Genetic effects on print exposure at age 12 were moderate (~26%) and correlated with those influencing reading fluency at 12 (genetic r = 0.89), indicative of a gene-environment correlation. These findings were largely consistent with quantitative genetic twin analyses that used both twins in each pair (n = 1,066-1,409).

Space and language in Williams syndrome: insights from typical development

One of the holy grails of cognitive science is to understand the causal chain that links genes and cognition. Genetic syndromes accompanied by cognitive effects offer natural experiments that can uniquely inform our understanding of this chain. In this article, we discuss the case of Williams syndrome (WS), which is characterized by a set of missing genes on chromosome 7q11.23, and presents with a unique cognitive profile that includes severe spatial impairment along with strikingly fluent and well-structured language. An early inference from this profile was the idea that a small group of genes could directly target one cognitive system while leaving others unaffected. Recent evidence shows that this inference fails. First, the profile within the spatial domain is varied, with relative strength in some aspects of spatial representation but severe impairment in others. Second, some aspects of language may fail to develop fully, raising the question of how to compare the resilience and fragility of the two key cognitive domains in this syndrome. Third, much research on the profile fails to place findings in the context of typical developmental trajectories. We explore these points and propose a new hypothesis that explains the unusual WS cognitive profile by considering normal mechanisms of cognitive development that undergo change on an extremely prolonged timetable. This hypothesis places the elements of the WS cognitive profile in a new light, refocuses the discussion of the gene-cognition causal chain for WS and other disorders, and more generally, underlines the importance of understanding cognitive structure in both typical and atypical development. WIREs Cogn Sci 2013, 4:693-703. doi: 10.1002/wcs.1258 Conflict of interest: The authors have declared no conflicts of interest for this article. For further resources related to this article, please visit the WIREs website.