Stochastic Gene Expression
Molecular noise in transcription & translation
Gene expression is inherently stochastic: transcription factors bind/unbind randomly, mRNA is produced in discrete bursts, and protein numbers fluctuate.
The noise η² = Var/Mean² = 1/⟨n⟩ + b/k_on (intrinsic + burst contributions).
Even genetically identical cells show wide protein-level variation — exploited for bet-hedging, cell fate decisions, and bistable switches.