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We tested the structure and magnitude of genetic and environmental influences on the overlap among self-esteem, negative emotionality, and major depression symptoms in adolescent girls ( N=706) from the Minnesota Twin Family Study. Genetic and environmental influences on all three operated via a general, heritable factor. Genetic influences explained the majority of overlap among the three constructs, as well as most of the variance in self-esteem and negative emotionality. Genetic influences on depression were more modest and largely due to genetic factors specific to depression. These findings support the theory that self-esteem, depression, and neuroticism represent aspects of a common temperamental core. The interrelations among the three constructs in mid-adolescence is consistent with their interrelations in adulthood. [ABSTRACT FROM AUTHOR]

Although religiousness is considered a protective factor against antisocial behaviors and a positive influence on prosocial behaviors, it remains unclear whether these associations are primarily genetically or environmentally mediated. In order to investigate this question, religiousness, antisocial behavior, and altruistic behavior were assessed by self-report in a sample of adult male twins (165 MZ and 100 DZ full pairs, mean age of 33 years). Religiousness, both retrospective and current, was shown to be modestly negatively correlated with antisocial behavior and modestly positively correlated with altruistic behavior. Joint biometric analyses of religiousness and antisocial behavior or altruistic behavior were completed. The relationship between religiousness and antisocial behavior was due to both genetic and shared environmental effects. Altruistic behavior also shared most all of its genetic influence, but only half of its shared environmental influence, with religiousness. [ABSTRACT FROM AUTHOR]

The relation between sociability and positive affect is one of the most often replicated results of research on personality and subjective well-being. It is shown how behavior genetics can contribute to our understanding of the covariance between sociability and positive emotionality. The results of a multimethod behavior-genetic study with 158 monozygotic and 120 dizygotic twins are reported. In this study, sociability and two components of positive emotionality (positive affect, energy) were assessed by self-report and other report. Additionally, positive state affect was assessed in five situations and aggregated across situations. The results showed that there are strong genetic correlations between all variables. Furthermore, there are substantive correlations between the nonshared environmental components of the different variables. Shared environmental influences, however, seemed to be unimportant for explaining the correlations between sociability and the different components of positive emotionality. The results are discussed with respect to their implications for future research on sociability and positive emotionality. [ABSTRACT FROM AUTHOR]

Recent studies have demonstrated substantial correlations between normal and abnormal personality traits. Yet little is known about how these correlations are mediated genetically and environmentally: Do normal and abnormal personality traits stem from the same underlying genes and environments? We addressed this question using data from 128 monozygotic and dizygotic twin pairs in the Minnesota Study of Twins Reared Apart (MISTRA). Additive genetic and nonshared environmental correlations between scales of the Minnesota Multiphasic Personality Inventory (MMPI)--an index of abnormal personality--and the Multidimensional Personality Questionnaire (MPQ)--an index of normal personality--were estimated. Results indicated that phenotypic correlations between normal and abnormal personality were mediated by genetic as well as environmental factors, although the magnitude of genetic mediation tended to be larger overall. Moreover, the patterns of phenotypic, genetic, and environmental relationships among the scales were similar, suggesting that influences on normal and abnormal personality act through systems common to both. It is suggested that future research focus on the neurogenetic substrates of these shared systems and how dysfunction in these systems influences development of disordered personality. [ABSTRACT FROM AUTHOR]

Analyzing data from Loehlin and Nichols's (1976) classic twin study, we computed measures of Masculine Instrumentality (M), Feminine Expressiveness (F), and Gender Diagnosticity (GD). Quantitative genetic modeling analyses of within-sex individual differences in M, F, and GD indicated that: (1) Additive genetic factors contribute significantly to individual differences in M, F, and GD. (2) The environmental effects on M, F, and GD tend to be nonshared. (3) The genetic and environmental components of individual differences in M, F, and GD tend not to show gender differences. Finally, (4) the estimated within-sex heritability of GD (.53) is significantly greater than the estimated within-sex heritabilities of either M (.36) or F (.38). [ABSTRACT FROM AUTHOR]