Phenotypic, genetic and non-shared environmental correlations among CGT, AGI and sexual orientation (attraction).

<p>Phenotypic, genetic and non-shared environmental correlations among CGT, AGI and sexual orientation (attraction).</p

Best fitting common pathway model.

<p>The figure shows standardized parameter estimates for the path coefficients of the common pathway model, selected as the most appropriate depiction of the data. The squares of the path coefficients provide an estimate of the variance explained by common and specific genetic and environmental components.</p

Intra-class correlations, cross-twin cross-trait correlations and heritabilities for CGT, AGI and both measures of sexual orientation.

<p>Heritability estimates and 95% CIs for all variables are calculated from the best-fitting, most parsimonious univariate AE model.</p><p>Note. Twin correlations for MZs/DZs are presented on the diagonal. Cross-twin cross-trait correlations for MZs are presented below the diagonal. Cross-twin cross-trait correlations for DZs are presented above the diagonal.</p

Percentage of women that checked each item of sexual attraction along with means (and standard deviations) for their respective CGT and AGI scores.

<p>Percentage of women that checked each item of sexual attraction along with means (and standard deviations) for their respective CGT and AGI scores.</p

Means (and standard deviations) for continuous demographic variables, CGT, AGI and sexual orientation (attraction), along with frequency data for discrete demographics for the whole sample and by zygosity group.

<p>*Unpaired two-tailed <i>t</i>-test and Mann-Whitney U-tests were used to test for mean differences in response frequencies.</p><p>**Two-sample test of proportions were used to explore differences in response frequencies.</p

Multivariate analysis of three models showing change in model fit (<i>χ</i>2) and degrees of freedom (<i>df</i>) when specified parameters are dropped from full ADE model (best fitting models in bold).

<p>AIC = Akaike Information Criterion. AIC describes the model with best goodness-of-fit combined with parsimony. BIC = Bayesian Information Criterion. −2LL = likelihood ratio chi-square test as a measure of goodness of fit.</p

Descriptive statistics of the raw data for female and male MZ and DZ twins including total number of individuals (n), means and standard deviations (s.d.) for the liver function test proteins and the major covariates included in the study.

<p>Note AST was not measured in male twins.</p

Genetic model fitting results for variation in liver function test proteins.

<p>The best fitting model is highlighted in grey. For each protein, full models (ACE & ADE) was compared to nested models (AE, CE, E) using a chi-squared test ΔX² = (X² sub model)−(X² full model) with the degrees of freedom equal to ΔDf = (Df sub model)−(Df full model). The degrees of freedom increases from the full to sub or nested models due to drop in the numbers of parameters estimated as one moves down the model hierarchy. To be judged a good-fit, models should have a non-significant chi-squared goodness-of-fit statistic (p>0.05). Note, C and D cannot be included together in the same model as in quantitative genetic studies of human populations they are confounded thus the full model is either ACE or ADE. Comparisons with the ACE full model are shown here. In all cases, ACE provided a better model fit than ADE with a smaller chi-squared goodness-of-fit statistic (data not shown).</p><p>Abbreviations: X² = chi-squared goodness-of-fit statistic; Df = degrees of freedom; ΔDf = (df sub model)−(df full model); Δ X² = (X² sub model)−(X² full model); P = P-Value; A = Additive genetic influence; C = Shared environmental variance; E = Unique environmental variance.</p

Results of the linear regression analyses of age, BMI and alcohol consumption on liver function test proteins.

<p>Abbreviations: N = number of individuals, F = F test statistic, Chi² = chi-square test, p = level of significance, R² = Adjusted R² explaining the proportion of the total variance explained.</p>¶<p>We report F-test statistics with 2 degrees of freedom from all regression analyses taking into account the relatedness between the twin pairs.</p>†<p>For alcohol consumption truncated Gaussian regression was used due to the half normal distribution of the alcohol data.</p