Bivariate path analysis of plasma lipids

Methods which allow for the analysis of the joint transmission of two phenotypes within a nuclear family are discussed and applied to the transmission of cholesterol and triglyceride. The analysis of data from 160 Caucasian nuclear families suggests a moderate degree of both genetic and residual environmental association between the two liquids. Although either the genetic correlation (ρG) or the residual environmental correlation (ρR) could be set equal to 0 without significantly increasing the residual χ², simultaneously setting both correlations equal to zero did significantly increase the χ² statistic. Consequently, the association between cholesterol and triglyceride could not be accounted for by common transmissible environmental effects alone.