Figure 1.

Simulation of a functional interaction

(A) Two genotypes in the protein coding sequence of a gene (alleles A and B, indicated by the green circle and red triangle) lead to differences in the function of a given enzyme, leading to differential throughput of a biological pathway (squares, representing the outcome Y) despite similar amounts of the input compound (stars, representing the environmental exposure E).

(B) Conceptual visualization of the E-Y effect modification.

(C) Results from simulation of a functional interaction.