However, these previous measurements of gene expression noise were made under several technical limitations that restricted the number of measurable cells and genes (Mitchel, 2018) banning the identification of subpopulations driven by non-genetic factors.  Nowadays, with the development of new single-cell RNA-seq methods based in droplets that allow measuring the whole transcriptome profile of thousands of cells with an unprecedented resolution (Tang, 2009; Zheng, 2018), our understanding of the origin, global distribution, and functional consequences of gene expression noise can be improved (Marinov, 2014; Kolodziejczyk, 2015).