Path diagram of phenotypic assortment model with genetic and cultural transmission from parents to offspring.

<p>Squares represent the phenotypes of a DZ twin pair (P_T1 and P_T2) with one extra sibling (P_Sib), and both parents (P_F and P_M). Latent factors are represented by circles and include A (additive genetic factor), D (dominance genetic factor), and E (non-shared environment). F represents vertical cultural transmission whereby the phenotype of the parents influences the environment of their offspring. Assortment of parents is modeled as a copath (i). Simultaneous genetic and cultural inheritance induces a correlation (s) between this environmental factor F and the genetic factor A. Path coefficients a, d and e represent the influence of latent factors on the phenotype. The variance due to vertical cultural transmission is represented by r and the variance of additive genetic factors by g.