TY - JOUR T1 - The meta-epigenomic structure of purified human stem cell populations is defined at <em>cis</em>-regulatory sequences JF - bioRxiv DO - 10.1101/007591 SP - 007591 AU - N. Ari Wijetunga AU - Fabien Delahaye AU - Yong Mei Zhao AU - Aaron Golden AU - Jessica C. Mar AU - Francine H. Einstein AU - John M. Greally Y1 - 2014/01/01 UR - http://biorxiv.org/content/early/2014/08/01/007591.abstract N2 - The mechanism and significance of epigenetic variability in the same cell type between healthy individuals are not clear. Here, we purify human CD34+ hematopoietic stem and progenitor cells (HSPCs) from different individuals and find that there is increased variability of DNA methylation at loci with properties of promoters and enhancers. The variability is especially enriched at candidate enhancers near genes transitioning between silent and expressed states, and encoding proteins with leukocyte differentiation properties. Our findings of increased variability at loci with intermediate DNA methylation values, at candidate “poised” enhancers, and at genes involved in HSPC lineage commitment suggest that CD34+ cell subtype heterogeneity between individuals is a major mechanism for the variability observed. Epigenomic studies performed on cell populations, even when purified, are testing collections of epigenomes, or meta-epigenomes. Our findings show that meta-epigenomic approaches to data analysis can provide insights into cell subpopulation structure. ER -