PT - JOURNAL ARTICLE AU - Lucy Ham AU - Rowan D. Brackston AU - Michael P.H. Stumpf TI - Extrinsic noise and heavy-tailed laws in gene expression AID - 10.1101/623371 DP - 2019 Jan 01 TA - bioRxiv PG - 623371 4099 - http://biorxiv.org/content/early/2019/04/30/623371.short 4100 - http://biorxiv.org/content/early/2019/04/30/623371.full AB - Noise in gene expression is one of the hallmarks of life at the molecular scale. Here we derive analytical solutions to a set of models describing the molecular mechanisms underlying transcription of DNA into RNA. Our Ansatz allows us to incorporate the effects of extrinsic noise – encompassing factors external to the transcription of the individual gene – and discuss the ramifications for heterogeneity in gene product abundance that has been widely observed in single cell data. Crucially, we are able to show that heavy-tailed distributions of RNA copy numbers cannot result from the intrinsic stochasticity in gene expression alone, but must instead reflect extrinsic sources of variability.