562,496 research outputs found
The correlation between reading and mathematics ability at age twelve has a substantial genetic component.
Full text linkDissecting how genetic and environmental influences impact on learning is helpful for maximizing numeracy and literacy. Here we show, using twin and genome-wide analysis, that there is a substantial genetic component to children's ability in reading and mathematics, and estimate that around one half of the observed correlation in these traits is due to shared genetic effects (so-called Generalist Genes). Thus, our results highlight the potential role of the learning environment in contributing to differences in a child's cognitive abilities at age twelve
Genetic covariation among facets of openness to experience and general cognitive ability
No full textGenetic and environmental sources of covariation among cognitive measures of verbal IQ, performance IQ (PIQ), academic achievement, 2-choice reaction time (CRT), inspection time (IT) and the 6 Openness facets of the NEO Personality Inventory-Revised (NEO PI-R) were examined. The number of twin and twin–sibling pairs ranged from 432 (182 MZ, 350 DZ/sibling) to 1023 (273 MZ, 750 DZ/sibling) for cognitive measures, and between 432 (90 MZ, 342 DZ/sibling) — 437 (91 MZ, 346 DZ/sibling) for Openness facets. Structural equation modeling best supported a model with a 3-factor additive genetic structure. A genetic general factor subsumed the 5 cognitive measures and 5 of the 6 Openness facets (Actions did not load significantly). A second additive genetic factor incorporated the 6 Openness facets, and a third additive genetic factor incorporated the 5 cognitive measures. Specific additive and dominance genetic effects were also evident, as were shared common and shared unique environmental influences, and specific unique environmental effects. The Openness facets of Ideas and Values evidenced the strongest phenotypic correlations with cognitive indices, particularly verbal measures. The genetic correlations among Openness facets and cognitive measures ranged from −.06 to .79. Results were interpreted as suggesting that Openness is related to general cognitive ability (g) through a genetic mechanism and that gengenders a minor but discernable disposition towards Openness for the majority of facets
Chapter 25 Pediatric twin studies
No full textPediatric twin studies have been very useful to understand the most common somatic health disorders in childhood. Twin methodology has been used to report on heritability as well as risk factors, comorbidities, and consequences for pediatric respiratory, autoimmune, and hemato-oncological diseases. Using advanced twin methodology in large twin populations, studies have been most useful to further the understanding of heritability and the role of early life risk factors, including those involved in the fetal origins or hygiene hypothesis, for the development of childhood somatic health disorders. Pediatric research questions have however not yet utilized twin methodologies as much as for mental health disorders and there is a great potential to pursue future studies. In this chapter, we have reviewed causes, comorbidities, and consequences of pediatric somatic health disorders and point toward future studies
Genetic influences on exercise participation in 37.051 twin pairs from seven countries
Full text linkBackground A sedentary lifestyle remains a major threat to health in contemporary societies. To get more insight in the relative contribution of genetic and environmental influences on individual differences in exercise participation, twin samples from seven countries participating in the GenomEUtwin project were used. Methodology Self-reported data on leisure time exercise behavior from Australia, Denmark, Finland, Norway, the Netherlands, Sweden and United Kingdom were used to create a comparable index of exercise participation in each country (60 minutes weekly at a minimum intensity of four metabolic equivalents). Principal Findings Modest geographical variation in exercise participation was revealed in 85,198 subjects, aged 19–40 years. Modeling of monozygotic and dizygotic twin resemblance showed that genetic effects play an important role in explaining individual differences in exercise participation in each country. Shared environmental effects played no role except for Norwegian males. Heritability of exercise participation in males and females was similar and ranged from 48% to 71% (excluding Norwegian males). Conclusions Genetic variation is important in individual exercise behavior and may involve genes influencing the acute mood effects of exercise, high exercise ability, high weight loss ability, and personality. This collaborative study suggests that attempts to find genes influencing exercise participation can pool exercise data across multiple countries and different instrument
Nature or Nurture? A Note on the Misinterpreted Twin Decomposition
Full text linkThe classical twin model has often been used to determine whether variation in outcomes such IQ, schooling and other behavioral traits, originate from genetic endowments or environmental factors. Despite some heavy criticism from prominent scholars, the model has recently reappeared in highly ranked economics journals to perhaps spark off a revival of the method. This article seeks to specify the assumptions which generate the apparently profound divide in viewpoints. A general problem is that most authors do not properly discuss the underlying assumptions of the twin model. It has partly led to a disarray of thoughts, concrete examples are provided, since the interpretation of the results and the risk for misleading interpretations are not spelled out. Therefore, perhaps surprisingly, a brief account of the theories behind the main assumptions of the twin model provides a useful contribution.genes; environments
A Twin Study of Early-Childhood Asthma in Puerto Ricans
Full text linkBackground:The relative contributions of genetics and environment to asthma in Hispanics or to asthma in children younger than 3 years are not well understood.Objective:To examine the relative contributions of genetics and environment to early-childhood asthma by performing a longitudinal twin study of asthma in Puerto Rican children ≤3 years old.Methods:678 twin infants from the Puerto Rico Neo-Natal Twin Registry were assessed for asthma at age 1 year, with follow-up data obtained for 624 twins at age 3 years. Zygosity was determined by DNA microsatellite profiling. Structural equation modeling was performed for three phenotypes at ages 1 and 3 years: physician-diagnosed asthma, asthma medication use in the past year, and ≥1 hospitalization for asthma in the past year. Models were additionally adjusted for early-life environmental tobacco smoke exposure, sex, and age.Results:The prevalences of physician-diagnosed asthma, asthma medication use, and hospitalization for asthma were 11.6%, 10.8%, 4.9% at age 1 year, and 34.1%, 40.1%, and 8.5% at 3 years, respectively. Shared environmental effects contributed to the majority of variance in susceptibility to physician-diagnosed asthma and asthma medication use in the first year of life (84%-86%), while genetic effects drove variance in all phenotypes (45%-65%) at age 3 years. Early-life environmental tobacco smoke, sex, and age contributed to variance in susceptibility.Conclusion:Our longitudinal study in Puerto Rican twins demonstrates a changing contribution of shared environmental effects to liability for physician-diagnosed asthma and asthma medication use between ages 1 and 3 years. Early-life environmental tobacco smoke reduction could markedly reduce asthma morbidity in young Puerto Rican children. © 2013 Bunyavanich et al
From observational to dynamic genetics
Full text linkTwin and family studies have shown that most traits are at least moderately heritable. But what are the implications of finding genetic influence for the design of intervention and prevention programs? For complex traits, heritability does not mean immutability, and research has shown that genetic influences can change with age, context, and in response to behavioral and drug interventions. The most significant implications for intervention will come when we move from observational genetics to investigating dynamic genetics, including genetically sensitive interventions. Future interventions should be designed to overcome genetic risk and draw upon genetic strengths by changing the environment
Twin Deficits or Distant Cousins? Evidence from India
Full text linkThe twin-deficits theory has intrigued economists and policy-makers alike for the past few decades. In a Keynesian economy, budget deficit increases the absorption of the economy, causes import expansions, and thereby, worsens the trade deficit. It also causes domestic interest rates to rise, domestic currency to appreciate, and thereby, contributes to trade deficits. Using monthly data over 1998-2009 and the bounds testing approach to cointegration, we find evidence that the twin-deficits theory holds for India in the short-run. Evident of the Ricardian Equivalence Hypothesis (REH), it appears that no such relation exists the long run.Bounds-Testing, Budget Deficit, Fiscal Stimulus, India, Trade Deficit, Twin Deficits
University of Washington Twin Registry: Poised for the Next Generation of Twin Research
Get PDFThe University of Washington Twin Registry is a unique community-based registry of twin pairs who join specifically to participate in scientific research. It was founded in 2002 to serve as a resource for investigators throughout the scientific community. Current enrollment exceeds 7,200 pairs, and plans are in place to increase enrollment to 10,000 pairs by 2015. In addition to serving as a recruitment base for new research studies, the registry maintains extensive and continually expanding survey data on physical and mental health, as well as a biorepository that includes DNA from more than 8,800 individual twins. The registry is engaged in linking member data to birth records and to diagnostic and procedure variables for hospital-based care provided to members in Washington State. It also incorporates several innovative variables relevant to the built and social environments, which were created by geocoding twin addresses and linking the resulting coordinates to geospatial information systems databases. This combination of existing data and biospecimens, characterizing a group of twins who are willing to participate in research, is a valuable resource for the new wave of twin studies. These include ‘omics’, epigenetics, gene-by-environment interactions, and other novel methods to understand human health
Twin deficits in Cambodia: An Empirical Study
Full text linkThis study examines the inter-linkages between Government budget balance, and external balance for a transition economy in South East Asia – Cambodia. The empirical results of the quarterly data between 1996 and 2006, support twin deficits hypothesis that is the budget deficits do cause external deficits, in the short run. These two macroeconomics variables are moving together in the long run. For implication, these findings provide an insight for the Cambodia''s policy design and formulation.Budget Deficits Cambodia Current Account Deficit Unit Root Tests
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