2019) in R (R Core Team, 2017). A diagram of the common factor genomic structural equation model (gSEM) is included in Figure 1. The variance of the common factor was fixed to 1 to identify the model without SNPs. Loadings from the common factor to genetic variance at each developmental period (λ12-17, λ18-25, λ26+) and the corresponding residual variances (U12-17,U18-25,U26+) were freely estimated.
