Stochastic Petri Net — Biochemical Gillespie Algorithm

Gene expression network: DNA → mRNA → Protein, with degradation. Each reaction is stochastic; the Gillespie SSA samples exact trajectories from the Chemical Master Equation. Circles=species, boxes=reactions.

Rates

System State

Time: 0.0
mRNA count: 0
Protein count: 0
⟨mRNA⟩ (det):
⟨Protein⟩ (det):
Gillespie SSA:
a_μ = propensity of rxn μ
τ = -ln(U₁)/Σa_μ
select rxn by U₂·Σa_μ