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Article
Assortative mating for Cigarette Smoking and for Alcohol Consumption in Female Australian Twins and their Spouses
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Article
Genetic Time-series Analysis Identifies a Major QTL for in vivo Alcohol Metabolism not Predicted by in vitro Studies of Structural Protein Polymorphism at the ADH1B or ADH1C Loci
After ingestion of a standardized dose of ethanol, alcohol concentrations were assessed, over 3.5 hours from blood (six readings) and breath (10 readings) in a sample of 412 MZ and DZ twins who took part in an...
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Article
Genetic and Social Determinants of Initiation and Age at Onset of Smoking in Australian Twins
Retrospective data on age at onset of smoking, reported by 3810 adult Australian twin pairs, were analyzed to determine the role of genetic and environmental factors in the onset of smoking. Results of nonmetr...
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Article
A Twin Study of Drinking and Smoking Onset and Latencies from First Use to Regular Use
The early onset of alcohol and tobacco use has been associated with increased risk for later substance abuse and dependence problems. This study investigated genetic and environmental influences on age at onse...
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Article
Distinguishing Population Stratification from Genuine Allelic Effects with Mx: Association of ADH2 with Alcohol Consumption
A universal problem in genetic association studies is to distinguish associations due to genuine effects of the locus under investigation, or linkage disequilibrium with a nearby locus that has a genuine effec...
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Article
Longitudinal Genetic Analysis of Menstrual Flow, Pain, and Limitation in a Sample of Australian Twins
Genetically informative longitudinal data about menstrual disorders allow us to address the extent to which the same genetic risk mechanisms are operating throughout the reproductive life cycle. We investigate...
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Article
Logistic regression analysis of twin data: Estimation of parameters of the multifactorial liability-threshold model
We extend the DeFries-Fulker regression model for the analysis of quantitative twin data to cover binary traits and genetic dominance. In the proposed logistic regression model, the cotwin's trait status,C, is th...
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Article
A model system for analysis of family resemblance in extended kinships of twins
The “Virginia 30,000” comprise 29,698 subjects from the extended kinships of 5670 twin pairs. Over 80 unique correlations between relatives can be derived from these kinships, comprised of monozygotic (MZ) and...
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Article
Testing hypotheses about direction of causation using cross-sectional family data
We review the conditions under which cross-sectional family data (e.g., data on twin pairs or adoptees and their adoptive and biological relatives) are informative about direction of causation. When two correl...
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Article
Religion and education as mediators of attitudes: A multivariate analysis
The transmission of social attitudes has been investigated as a possible model of cultural inheritance in a sample of 3810 twin pairs from the Australian National Health and Medical Research Twin Registry. Six...
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Article
Personality and reproductive fitness
The relationship between reproductive success (number of biological children) and personality was explored in 1101 postmenopausal females from the Australian twin registry. The quadratic response surface relat...
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Article
Religious affiliation in twins and their parents: Testing a model of cultural inheritance
The transmission of religious affiliation is analyzed in a sample of 3810 Australian twin pairs and their parents. Twins were classified by sex, zygosity, and whether they were living together or apart. Analys...
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Article
The effects of social homogamy and cultural inheritance on the covariances of twins and their parents: A LISREL model
In general, models involving parent-offspring transmission are not possible to specify in LISREL due to the complex constraints implied by assortative mating and genotype-environmental correlation. In this sho...
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Article
Fitting genetic models with LISREL: Hypothesis testing
A brief introduction to the mathematical theory involved in model fitting is provided. The properties of maximum-likelihood estimates are described, and their advantages in fitting structural models are given....
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Article
Testing structural equation models for twin data using LISREL
Simple genetic models can be fitted to twin data using software packages such as LISREL (Jöreskog and Sörbom, 1986a). After discussion of data preparation and routine checks on possible violation of assumption...
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Article
A note on computing the chi-square noncentrality parameter for power analyses
Power calculations for a variety of research designs used in behavior genetics require the determination of a chi-square noncentrality parameter. For many purposes published tables are adequate, but for cases ...
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Article
Testing genetic models for multiple symptoms: An application to the genetic analysis of liability to depression
A model is presented which allows for the contribution of genes and environment to categorical data on multiple symptoms. The model distinguishes between parameters needed to express the relationship between a...
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Article
Genetic and environmental factors in primary dysmenorrhea and its relationship to anxiety, depression, and neuroticism
Over 1200 pairs of female monozygotic and dizygotic twins with regular menses reported on the amount of flow, severity of pain, and degree of limitation experienced during menstruation. Fifty-two percent of th...
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Article
Social inequality and assortative mating: Cause or consequence?
Johnsonet al. (Behav. Genet. 17:1–7, 1987) have interpreted an apparent decline in assortative mating for educational attainment in Hawaii as being a consequence of increased social mobility and increased access ...
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Article
A theory of developmental change in quantitative phenotypes applied to cognitive development
A model is presented for the changes in familial resemblance as a function of age. The model allows for separate developmental components of genetic and environmental effects and for the influence of earlier p...