Fig. 3.

Trajectories of average BMI over time for actual QNTS data and simulated gene-time-environment interaction scenarios. Example datasets from each simulation scenario having an interaction effect on the rate of change of BMI over time are compared to the actual QNTS data. Trajectories of average BMI at each time point based on actual QNTS data are grouped by zygosity status; MZ (monozygotic twin) and DZ (dizygotic twin). Averages of simulated BMI at each time point and their trajectories are grouped by genetic (G) and environmental (E) factor levels. Genetic factor coded as 0, 1, and 2 for the number of minor alleles. Environment factor coded as 1 or 0 for presence or absence of the environmental exposure. Simulated data generated for both interaction effect on the rate of change over time scenarios and no interaction effect null scenarios