What does it mean if a gene has a heterogeneous expression? Does it describe the differences of patterns of expression of that particular gene in a population of cells that are identical? The papers I have found did not really elaborate on what it meant, and I do not know where else to find the definition.
In particular, I want to understand heterogeneity in the context of stem cells. In the paper by Angarica and Sol, 2016, it reads:
“Experimental studies at the single-cell level have revealed that embryonic stem cells (ESCs), and more generally pluripotent stem cells (PSCs), exhibit significant gene expression heterogeneity.”
“Single-cell studies have allowed gene clustering, depending on the levels of heterogeneity in the gene expression landscape in PSCs.”
Does it have more to do with the variation of its expression in the population?
“In mouse ESCs genes exist that are uniformly expressed in most cells and exhibiting a unimodal distribution (Oct4, Rest, Tcf3, Sal4); other genes exhibit bimodal expression and are expressed in some populations but not in others (Nanog, Rex1, Tet1, Esrrb), and yet another group of genes display sporadic expression (Neurod1, Klf4, Otx2, Pax6) and are undetected in most cells but highly expressed in some speciﬁc subpopulations.”