The influence of genetic imprinting on IQ and other traits are

Not deterministic, that's why you can observe "regression toward the mean" to some extent among generations. Proponents of Eugenics (foundation for Fascism) made a serious mistake of thinking genetic imprinting is purely determinstic and you can therefore "engineer" a taller, more blond, more "intelligent" human race by eleminating potential parents that don't bear these traits. Little did they know, the lack of expression of certain genes is not equivalent of not carrying that genes, and vice versa, carrying certain genes does not guarantee the expression of those genes.