Behavior Genetics

, Volume 24, Issue 2, pp 119–139 | Cite as

Multivariate genetic analysis of twin-family data on fears: Mx models

  • Michael C. Neale
  • Ellen E. Walters
  • Lindon J. Eaves
  • Hermine H. Maes
  • Kenneth S. Kendler


We describe the implementation of multivariate models of familial resemblance with the Mx package. The structural equation models allow for the effects of assortative mating, additive and dominant genes, common and specific environment, and both genetic and cultural transmission between generations. Two approaches are compared: a correlational one based on Fulker and a factor model described by Phillips and Fulker. Both are illustrated by application to published data on social fears and fear of leadership measured in monozygotic and dizygotic twins and their parents. In the example data, genetic dominance yields a more parsimonious explanation of the data than does cultural transmission, although neither is needed to obtain a good fit to the data. A model of reduced genetic correlation between generations also fits the data but has inherent limitations in this sample. Extensions to sex-limitation and more complex models are discussed.

Key Words

Multivariate genetic analysis twin-family data fears Mx models cultural transmission genetic dominance assortative mating 


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Copyright information

© Plenum Publishing Corporation 1994

Authors and Affiliations

  • Michael C. Neale
    • 1
  • Ellen E. Walters
    • 1
  • Lindon J. Eaves
    • 1
    • 2
  • Hermine H. Maes
    • 2
  • Kenneth S. Kendler
    • 1
    • 2
  1. 1.Department of PsychiatryMedical College of VirginiaRichmond
  2. 2.Department of Human GeneticsMedical College of VirginiaRichmond

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