Figure 3.

Comparison of (a) the average and (b) the variance of the monomer M number computed for the gene regulation cascade in the time interval t=[0,2000]: the Gillespie simulation (circle), the reduced Langevin approximation (solid line), and without fast noise (dashed line). δ=0.01, α₀=0.1, α₁=1.0, λ=0.2, θ=15, k=0.05, and β=3 with the initial condition (m,N_ϕ0,N_ϕ1,n)=(0,1,0,0).