ORCID Profile
0000-0002-6075-9882
Current Organisation
University of Colorado at Boulder
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Publisher: Springer Science and Business Media LLC
Date: 19-02-2012
DOI: 10.1038/NG.1108
Publisher: Wiley
Date: 16-07-2009
DOI: 10.1002/AJMG.A.32973
Publisher: Springer Science and Business Media LLC
Date: 27-06-2012
DOI: 10.1038/NG0712-831A
Publisher: Springer Science and Business Media LLC
Date: 11-2005
DOI: 10.1007/S10519-005-6041-7
Abstract: Studies using the classical twin design often conclude that most genetic variation underlying personality is additive in nature. However, studies analyzing only twins are very limited in their ability to detect non-additive genetic variation and are unable to detect sources of variation unique to twins, which can mask non-additive genetic variation. The current study assessed 9672 MZ and DZ twin in iduals and 3241 of their siblings to investigate the environmental and genetic architecture underlying eight dimensions of personality: four from Eysenck's Personality Questionnaire and four from Cloninger's Temperament and Character Inventory. Broad-sense heritability estimates from best-fitting models were two to three times greater than the narrow-sense heritability estimates for Harm Avoidance, Novelty Seeking, Reward Dependence, Persistence, Extraversion, and Neuroticism. This genetic non-additivity could be due to dominance, additive-by-additive epistasis, or to additive genetic effects combined with higher-order epistasis. Environmental effects unique to twins were detected for both Lie and Psychoticism but accounted for little overall variation. Our results illustrate the increased sensitivity afforded by extending the classical twin design to include siblings, and may provide clues to the evolutionary origins of genetic variation underlying personality.
Publisher: SAGE Publications
Date: 07-2013
Abstract: IQ predicts many measures of life success, as well as trajectories of brain development. Prolonged cortical thickening observed in in iduals with high IQ might reflect an extended period of synaptogenesis and high environmental sensitivity or plasticity. We tested this hypothesis by examining the timing of changes in the magnitude of genetic and environmental influences on IQ as a function of IQ score. We found that in iduals with high IQ show high environmental influence on IQ into adolescence (resembling younger children), whereas in iduals with low IQ show high heritability of IQ in adolescence (resembling adults), a pattern consistent with an extended sensitive period for intellectual development in more-intelligent in iduals. The pattern held across a cross-sectional s le of almost 11,000 twin pairs and a longitudinal s le of twins, biological siblings, and adoptive siblings.
Publisher: Public Library of Science (PLoS)
Date: 12-04-2012
Publisher: Cold Spring Harbor Laboratory
Date: 21-05-2019
DOI: 10.1101/643304
Abstract: Using data from 5,500 adolescents from the National Longitudinal Study of Adolescent to Adult Health, Domingue et al. (2018) claimed to show that friends are genetically more similar to one another than randomly selected peers, beyond the confounding effects of population stratification by ancestry. The authors also claimed to show ‘social-genetic’ effects, whereby in iduals’ educational attainment (EA) is influenced by their friends’ genes. Neither claim is justified by the data. Mathematically we show that 1) although similarity at causal variants is expected under assortment, the genome-wide relationship between friends (and similarly between mates) is extremely small (an effect that could be explained by subtle population stratification) and 2) significant association between in iduals’ EA and their friends’ polygenic score for EA is expected under homophily with no socio-genetic effects.
Publisher: Springer Science and Business Media LLC
Date: 10-11-2013
Publisher: Public Library of Science (PLoS)
Date: 04-04-2013
Publisher: Elsevier BV
Date: 03-2013
Publisher: Cambridge University Press (CUP)
Date: 02-2009
DOI: 10.1375/TWIN.12.1.19
Abstract: Modeling the data from extended twin pedigrees allows the estimation of increasing complex covariance relationships in which the effects of cultural transmission, nonrandom mating and genotype x environment covariation can be incorporated. However, the power to detect these effects in existing data sets has not yet been examined. The present study examined the effects that different family structures (i.e., the ratio of MZ to DZ families and the importance of cousins vs. avuncular relatives) have on statistical power. In addition, we examined the power to detect genetic and environmental effects within the context of two large data sets (VA30K and the OZVA60K). We found that power to detect additive genetic and cultural transmission effects were maximized by over s ling MZ families. In terms of ascertainment, there was little difference in power between s les that had focused on recruiting a third generation (the children of twins) versus those that had focused on recruiting the siblings of the twins. In addition, we examined the power to detect additive and dominant genetic effects, cultural transmission and assortative mating in the existing VA30K and OZVA60K s les, under two different models of mating: phenotypic assortment and social homogamy. There was nearly 100% power to detect assortative mating and cultural transmission, against a background of small additive and dominant genetic and familial environmental effects. In addition, the power to detect additive or dominant genetic effects quickly asymptoted, so that there was almost 100% power to detect effects explaining 20% or more of the total variance. These results demonstrate that the Cascade model has sufficient power to detect parameters of interest in existing datasets. Mx scripts are available from www.vipbg.vcu.edu/~sarahme/cascade .
Publisher: SAGE Publications
Date: 30-12-2014
Abstract: For women, choosing a facially masculine man as a mate is thought to confer genetic benefits to offspring. Crucial assumptions of this hypothesis have not been adequately tested. It has been assumed that variation in facial masculinity is due to genetic variation and that genetic factors that increase male facial masculinity do not increase facial masculinity in female relatives. We objectively quantified the facial masculinity in photos of identical ( n = 411) and nonidentical ( n = 782) twins and their siblings ( n = 106). Using biometrical modeling, we found that much of the variation in male and female facial masculinity is genetic. However, we also found that masculinity of male faces is unrelated to their attractiveness and that facially masculine men tend to have facially masculine, less-attractive sisters. These findings challenge the idea that facially masculine men provide net genetic benefits to offspring and call into question this popular theoretical framework.
Publisher: Wiley
Date: 21-05-2012
Publisher: Elsevier BV
Date: 09-2013
Publisher: Cambridge University Press (CUP)
Date: 02-2009
DOI: 10.1375/TWIN.12.1.8
Abstract: The classical twin design uses data on the variation of and covariation between monozygotic and dizygotic twins to infer underlying genetic and environmental causes of phenotypic variation in the population. By using data from additional relative classes, such as parents, extended twin family designs more comprehensively describe the causes of phenotypic variation. This article introduces an extension of previous extended twin family models, the Cascade model, which uses information on twins as well as their siblings, spouses, parents, and children to differentiate two genetic and six environmental sources of phenotypic variation. The Cascade also relaxes assumptions regarding mating and cultural transmission that existed in previous extended twin family designs. The estimation of additional parameters and relaxation of assumptions is potentially important, not only because it allows more fine-grained descriptions of the causes of phenotypic variation, but more importantly, because it can reduce the biases in parameter estimates that exist in earlier designs.
Publisher: Springer Science and Business Media LLC
Date: 18-09-2011
DOI: 10.1038/NG.940
Publisher: Wiley
Date: 30-01-2014
DOI: 10.1002/AJMG.B.32217
Publisher: Springer Science and Business Media LLC
Date: 16-12-2009
Publisher: Cambridge University Press (CUP)
Date: 10-2008
Abstract: Lummaa et al. (2007) presented historical data collected from twins born in Finland between 1734 and 1888 which suggested that females ( N = 31) born as part of an opposite sex (OS) twin pair were 25% less likely to reproduce than female twins ( N = 35) born as part of a same sex (SS) pair. They hypothesized that this reduction in fitness was due to masculinization of the female fetus via prenatal effects of the hormones of a male fetus. Because such masculinization would presumably take place in modern populations as well, it would seem important to establish to what degree it does so, and if so, whether reproduction is affected. We therefore address the question of reproduction differences in in idual female twins from same-sex ( N = 1979) and opposite-sex ( N = 913) dizygotic pairs in studies carried out in Australia, the Netherlands, and the United States. In all three s les, there were no differences in the number of children or age of first pregnancies in women from same sex pairs compared to those from opposite sex pairs. Similarly, there were no differences in psychological femininity between women from pairs of the same or opposite sex.
Publisher: Springer Science and Business Media LLC
Date: 26-11-2018
Publisher: Springer Science and Business Media LLC
Date: 27-05-2014
DOI: 10.1038/NN.3708
Publisher: Cambridge University Press (CUP)
Date: 02-2009
DOI: 10.1375/TWIN.12.1.26
Abstract: The extended twin kinship design allows the simultaneous testing of additive and nonadditive genetic, shared and in idual-specific environmental factors, as well as sex differences in the expression of genes and environment in the presence of assortative mating and combined genetic and cultural transmission (Eaves et al., 1999). It also handles the contribution of these sources of variance to the (co)variation of multiple phenotypes. Keller et al. (2008) extended this comprehensive model for family resemblance to allow or a flexible specification of assortment and vertical transmission. As such, it provides a general framework which can easily be reduced to fit subsets of data such as twin-parent data, children-of-twins data, etc. A flexible Mx specification of this model that allows handling of these various designs is presented in detail and applied to data from the Virginia 30,000. Data on height, body mass index, smoking status, church attendance, and political affiliation were obtained from twins and their families. Results indicate that biases in the estimation of variance components depend both on the types of relative available for analysis, and on the underlying genetic and environmental architecture of the phenotype of interest.
Publisher: Springer Science and Business Media LLC
Date: 14-01-2019
Publisher: Elsevier BV
Date: 02-2013
Publisher: Springer Science and Business Media LLC
Date: 11-08-2202
DOI: 10.1038/NG.2711
No related grants have been discovered for MATTHEW KELLER.