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Estimates of the heritability of political and social attitudes suggest a surprising level of genetic influence but typically have been based on polychoric correlations of just twins, leaving the results open to question. In this paper, we add parents and non-twin full siblings to data on twins and estimate heritability with structural equation models. Among other things, these data and procedures correct for possible violations of the random mating and equal environments assumptions. With these improvements, estimates continue to indicate the political and social attitudes are heritable, perhaps even to a greater extent than was indicated by more limited data and more simplistic estimation techniques. Once again the conclusion has to be that genetics plays a role in the formation of political and social attitudes. The next step in this research stream should be the identification of the individual genes responsible for the persistently strong and consistently reported heritability of attitudes. ..PAT.-Unpublished Manuscript [ABSTRACT FROM AUTHOR]

Empirical work in behavior genetics consistently indicates a strong heritable component for political and social attitudes; however, these previous studies, relying as they do primarily on the classic twin design, are unable to identify the particular genes that are relevant to politics. Consequently, the next step in this research stream is to search for the specific genes responsible for the sizable heritability estimates. In this paper, we introduce two techniques frequently employed in genetics: genome-wide linkage scans and allelic association studies and apply them to a limited conception of political and personality phenotypes. Initial investigation reveals no clear genetic focal point of political temperaments, a finding that could suggest the need for larger samples and richer measures of the political phenotype but that in all likelihood is better seen as an indication that complex genetic traits such as political orientations entail so many genes, so many biological systems, and so many gene-environment interactions that the search for one gene, or even a small group of individual genes is unlikely to produce quick and straightforward results. ..PAT.-Unpublished Manuscript [ABSTRACT FROM AUTHOR]