non-significant (Kraft et al. 2007). To facilitate evaluation of the goodness-of-fit for both main effect and interaction models, we present Akaike’s information criterion (AIC) for all genetic analyses. AIC is a log-likelihood based measure of model fit that penalizes for model complexity (Akaike 1974). Lower AIC values are indicative of better-fitting models; here we present the reduction in AIC relative to the non-genetic base model (Equation 1).
