While it is unfortunate not to have good estimates of separate additive and nonadditive genetic variance components for Cloninger's scales, it should be remembered that a greater proportion of a trait's genetic variation is expected to be nonadditive if it is maintained by mutation-selection balance than if it is maintained by selective neutrality, pleiotropic balancing selection, or environmental heterogeneity. As such, our conclusion that genetic variation in personality traits is best explained by mutation-selection balance would hold regardless of the extent to which the gap between h2(SNPs) and H2 is due to rare variants or genetic nonadditivity.
