mRNA and protein fluctuations from bursty gene activation
mRNA: 0 | Protein: 0 | Gene: OFF
Genes toggle between active (ON) and silent (OFF) states. When ON, mRNA is produced in bursts; proteins are synthesized from mRNA. The Fano factor (variance/mean) of mRNA copy number is 1+b (b=burst size), exceeding Poisson noise. High burst rate with low copy number creates large cell-to-cell variability. The histogram shows the stationary mRNA distribution (negative binomial).