Genetic analysis of personality traits and alcoholism using a mixed discrete continuous trait variance component model

Bivariate analyses can improve power to detect linkage. This paper describe s one application of a bivariate variance component method for estimating j oint likelihoods of a continuous and a discrete trait. This method is appli ed to the Collaborative Study on the Genetics of Alcoholism data set to inv estigate the relationship between personality traits derived from the tridi mensional personality questionnaire (TPQ) and alcoholism. The results indic ate that the novelty-seeking subscale of the TPQ and alcoholism share a str ong and significant genetic correlation (rho(G) = 0.83) and modest environm ental correlation (rho(E)= 0.31). When both traits are considered jointly i n a multipoint linkage model compared with the alcoholism trait alone, ther e is an improvement in the ability to detect and localize a quantitative tr ait locus on chromosome 4. (C) 1999 Wiley-Liss, Inc.