Robert Plomin

..The present article considers reasons for the missing heritability problem and possible solutions...

..Research that focuses on quantitative traits - including the low and high ends of normal distributions - could have far-reaching implications for the diagnosis, treatment and prevention of the problematic extremes of these traits...

..However, a smaller proportion of the phenotypic intercorrelations appears to be explained by genetic influences for high abilities...

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..Here we assess whether this finding extends to language and general cognitive disabilities, as well as replicating the earlier finding for reading and mathematics in an older and larger sample...

..01 at age 11. These findings suggest that expression of FTO may become stronger throughout childhood. Increases in heritability may also be due to children increasingly selecting environments correlated with their genetic propensities...

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..When the sample was increased by adding females, 2 additional SNPs were nominally significant (P < .05). These 3 SNPs, however, showed no significant association in transmission disequilibrium analyses of diagnosed ASD families...

..Understanding what these increasingly important shared environmental influences are could lead to interventions that encourage engagement in science throughout the lifespan...

..The evidence however is inconsistent. Other studies have reported an effect in the opposite direction (higher heritability in lower SES), or no moderation of the genetic effect on intelligence...

..The basis for this association is poorly understood. How early language is related to each of the triad of impairments characteristic of ASDs is also in need of clarification...

..Genetic overlap was significant but moderate across all raters. These findings are discussed in relation to population screening for autism and future genetic research...

..To understand the overlap between the etiology of obesity and normal variation in BMI in children...

..It should therefore be possible to identify "SPA genes" that predict school achievement independently of "IQ genes."..

..The purpose of the present study was to test the developmental origins of some of these associations in a large longitudinal sample of children...

..Differences in identical twins' neonatal problems correlated weakly with their difference scores on autistic-like features (r = .01-.06)...

..The pervasiveness of genetic influence in how and how much children learn is compatible with an active view of learning in which children create their own educational experiences in part on the basis of their genetic propensities...

..We conclude that Internet testing can be reliable and valid for collecting cognitive test data on large samples even for children as young as 10 years...

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..A surprising finding emerging from multivariate quantitative genetic studies across diverse learning abilities is that most genetic influences are shared: they are "generalist", rather than "specialist"...

..This study takes an individual differences approach to determine the degree of phenotypic and aetiological overlap between autistic traits and ADHD behaviours in the general population...

..The identification of specific nonshared environments responsible for the variance in behaviour problems is a key challenge...

..57 and a shared environmental correlation of .65. These findings set constraints on how genetic and environmental variation affects the developing brain...

..The 4927 children in this genotyped sample have also been studied at 7, 9 and 12 years of age on measures of mathematical ability, as well as on other cognitive and learning abilities...

..However, the stability and change of these genetic influences and the predictive relationships underlying this association longitudinally remain unclear...

..Larger samples, denser arrays and multiple replications will be necessary in the hunt for the genetic variants that influence human cognitive ability...

..Thus, hyperactivity-impulsivity may serve to exacerbate inattentiveness over time. Findings are discussed in the context of developmental changes in ADHD symptoms...

..However, genetic influences on disruptive behavior did not explain why household chaos was heritable...

..In contrast, genetic factors remain stable from middle childhood through to early adolescence, and account for the phenotypic continuity in language skills across these two stages...

..41-0.60). Shared environmental influences were moderate (0.28, 0.19-0.37). We conclude that genetic variation contributes substantially to high g in Australia, the Netherlands, the United Kingdom and the United States...

..Future genetic studies should investigate the ADHD dimensions separately...

..g., eQTLs) and correlates (e.g., psychopathology) of individual differences in gene expression...

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..These findings impact our understanding about the origin of individual phenotypic differences and have implications for genetic studies of complex disease...

..We focus on findings that go beyond merely estimating heritability. We use learning abilities and disabilities as examples...

..We demonstrate that this approach can be effectively applied to the truly genomewide Affymetrix GeneChip Mapping 500 K Array...

..Similar to GWA analyses of other complex traits, it is likely that most of the heritable variation in environmental measures such as family chaos is due to many genes of very small effect size...

..The possible neural basis underlying this association is discussed...

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..In contrast, though more varied, heterotypic continuity between some traits (i.e. the change from one type of anxiety-related behaviour into another over time) was mainly due to shared-environmental factors...

..We present a set of software tools for processing SNPMaP (SNP microarrays and pooling) data from CEL files to Relative Allele Scores in the rich R statistical computing environment...

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..We conclude that, despite the considerable differences in mathematics curricula from 7 to 9 years, the same genetic effects largely operate at the two ages...

..This study investigated, in a community sample, the aetiology of ADHD-like traits and the aetiological overlap between the two dimensions that define the ADHD disorder...

..This method generates accurate quantitative assessments of group DNA methylation averages, reducing the time, cost and amount of DNA starting material required for large-scale epigenetic investigation of disease phenotypes...

..We illustrate this approach using a study of cognitive abilities involving over 5,000 pairs of twins...

..We conclude that low mathematical performance is the quantitative extreme of the same genetic and environmental factors responsible for variation throughout the distribution...

..10, p < .05). These results indicate that MZ twins experience the classroom differently and that differences in their experience are associated with differences in their achievement...

..This suggests that individual differences in mathematical ability are reflected in differential brain response during approximation...

..The heritability difference was even more pronounced in magnitude when hyperactive symptoms were controlled. CU traits thus appear to index one valid way of sub-typing children with early-onset AB...

..66 of the estimated heritability, reaffirming that cognitive abilities are heritable. Larger sample sizes alone will be sufficient to identify many of the genetic variants that influence cognitive abilities...

..Recent evidence suggests DNA methylation can be influenced by cis-acting DNA sequence variation, that is, DNA sequence variation located nearby on the same chromosome...

..A callous and unemotional disposition is an indicator of early-onset antisocial behaviour...

..What are the implications of these advances for identifying genes responsible for the high heritability of many behavioural disorders and dimensions in childhood?..

..The TEDS dataset is proving valuable in genome-wide association research that tries to identify some of the many genes responsible for the ubiquitous heritability of behavior...

..Future studies should conduct formal tests of Fetal Genotype x Maternal Smoking interactions...

..To assess the genetic and environmental etiology of the co-occurence of ADHD symptoms and reading difficulties using the largest sample to date, distinguishing two dimensions of ADHD and two of reading...

..Twin data suggest largely nonoverlapping genes acting on each of these traits. At the cognitive level, too, attempts at a single explanation for the symptoms of autism have failed. Implications for research and treatment are discussed...

..TEDS represents an outstanding resource for investigating the developmental effects of genes and environments on complex quantitative traits from childhood to young adulthood and beyond...

..Genetic influences on reading are substantial and stable during the elementary school years despite the shift from "learning to read" to "reading to learn."..

..The contribution of genetic factors in the persistence of and early recovery from stuttering was assessed...

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..Such an approach can be readily applied to the assessment of disease phenotypes reducing the time, cost and amount of DNA starting material required for large-scale epigenetic analyses...

..That is, the genetic input into brain structure and function is general not specific...

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