Gene expression noise in development: genome-wide dynamics

Gene expression noise underlies cell-to-cell variability in RNA and protein levels of a seemingly homogeneous population of cells. Emerging evidence suggests a functional role for this variability in the specification of cell fates during mammalian development. Advances in genome-wide and single-cell technologies now enable the quantification and deciphering of transcriptome variability with increasing precision. In this review, we highlight recent insights into the significance of gene expression noise during early embryogenesis, focusing on RNA variability. We discuss new approaches to further quantify and unravel different sources of gene expression noise and how this yields insights into early mammalian development.