title: Replication of a gene-environment interaction Via Multimodel inference: additive-genetic variance in adolescents' general cognitive ability increases with family-of-origin socioeconomic status.
abstract: The present study of general cognitive ability attempts to replicate and extend previous investigations of a biometric moderator, family-of-origin socioeconomic status (SES), in a sample of 2,494 pairs of adolescent twins, non-twin biological siblings, and adoptive siblings assessed with individually administered IQ tests. We hypothesized that SES would covary positively with additive-genetic variance and negatively with shared-environmental variance. Important potential confounds unaddressed in some past studies, such as twin-specific effects, assortative mating, and differential heritability by trait level, were found to be negligible. In our main analysis, we compared models by their sample-size corrected AIC, and base our statistical inference on model-averaged point estimates and standard errors. Additive-genetic variance increased with SES-an effect that was statistically significant and robust to model specification. We found no evidence that SES moderated shared-environmental influence. We attempt to explain the inconsistent replication record of these effects, and provide suggestions for future research.
authors.affiliation: Department of Psychology, University of Minnesota, 75 E. River Rd, Minneapolis, MN, 55455, USA, rkirkpatrick2@vcu.edu.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Kirkpatrick
authors.forename: Matt
authors.initials: M
authors.lastname: McGue
authors.forename: William G
authors.initials: WG
authors.lastname: Iacono
mesh_terms: D000293:Adolescent; D000300:Adoption; D001699:Biometry; D003071:Cognition; D004777:Environment; D005260:Female; D059647:Gene-Environment Interaction; D014644:Genetic Variation; D006801:Humans; D007360:Intelligence; D007361:Intelligence Tests; D008297:Male; D008910:Minnesota; D015233:Models, Statistical; D010290:Parents; D010641:Phenotype; D018401:Sample Size; D035781:Siblings; D012923:Social Class; D014429:Twins, Dizygotic / Q000235:genetics; D014430:Twins, Monozygotic / Q000235:genetics