Genome-wide profile of 5-hydroxymethylcytosine (5-hmC) in H9 human embryonic stem cells (hESCs)

The link between single cell variation and population level fate choices lacks an explanation despite extensive observations of gene expression and epigenetic variation among individual cells. Here, we found that single human embryonic stem cells (hESCs) have different and biased differentiation potentials toward either neuroectoderm or mesendoderm depending on their G1 lengths before the onset of differentiation. Single cell variation in G1 length establishes a probability distribution in which increased variation biases stem cells toward neuroectoderm. Although sister stem cells generally share G1 lengths, a variable proportion of cells have asymmetric G1 lengths, which maintains the population dispersion. WNT levels control the G1 length distribution apparently as a means of priming the fate of hESC populations once they undergo differentiation. Global 5-hydroxymethylcytosine levels are regulated by G1 length and thereby link G1 length to differentiation outcomes of hESCs. Our findings suggest G1 length distribution links intra-population heterogeneity to population outcome.