Fig. 1: Conceptual model of how parental genome, parental SES and offspring genome influence verbal ability.
From: Socioeconomic and genomic roots of verbal ability from current evidence
(An arrowed line indicates a causal effect; a double-arrowed line indicates a correlation. Solid lines represent observed relationships while interrupted lines represent unobserved relationships). a While offspring genome receives 50% of genetic alleles from each parent’s genome randomly (path A), parental SES is subject to the influence of all parental alleles (100% from each parent, (path B). b Offspring genome and parental SES are correlated (path C) due to the shared alleles between offspring genome and the subcomponent of the genomic component in parental SES (path D). c The same set of alleles from offspring and parents act on the subcomponent shared between parents and offspring; the subcomponent not shared with offspring is only acted upon by parental alleles not transmitted to offspring. The two subcomponents are hypothesized to be about the same. d In regression of verbal ability, the effects of offspring genome and parental SES are expected to be reduced because of the correlation. e The size of reduction in the offspring-genome effect may reflect the size of an overestimate in a regression in which parental SES is not included. f The effect of parental SES is reduced because the inclusion of offspring genome removes about one half of the entire genomic component in parental SES. The total size of the genetic component in parental SES is reasoned to be about twice as large as the reduction in the effect of parental SES when offspring genome is included.
