What does marginal genetic effect mean？

[WZo0o]

Dear GEM team,

Could you tell me the meaning of marginal genetic effect and the difference between marginal genetic effect and genetic main effect?

Thanks

[Han Chen]

We use the term "marginal genetic effect" to denote the effect of a genetic variant in the absence of gene-environment interaction terms (i.e., in a regular GWAS). In contrast, genetic main effect in our model means the effect of a genetic variant in the presence of gene-environment interactions. Note that genetic main effect needs to be interpreted at specific E values (0 if E is not centered, and the mean of E if E is centered).

Han

[WZo0o]

Thanks for your reply.