To determine the functional consequences of donor-related transcriptional and epigenetic differences, we differentiated iPSC lines toward the hematopoietic lineage using a previously described protocol (Ronn et al., 2015, Woods et al., 2011). We selected iPSC lines derived from two donors (T42 and T55) showing the largest transcriptional and epigenetic intra-line variability (Figure 1D). We used fluorescence-activated cell sorting (FACS) to identify frequencies of hematopoietic cells (CD45+), progenitors (CD45+ CD34+), and more developmentally immature hematopoietic cells (CD43+) (Figure 4A). There was no difference between isogenic F- and B-iPSC lines (Figure 4B). Hematopoietic and hematopoietic progenitor cells showed similar frequencies when we compared iPSC differentiation potential between two donors (Figure 4). However, donor T42 yielded significantly fewer mature hematopoietic cells than T55 (Figure 4C). Interestingly, microscopic analysis revealed fewer large hemoglobinized erythroid cell clusters in iPSC lines derived from donor T42 than from T55 (Figure 5A). FACS analysis using erythroblast markers (CD45− CD33 − glycophorin A [GPA]+, transferrin [CD71]+) confirmed the reduced erythroid potential of T42 iPSC lines compared with T55 (Figures 5B and 5C). To evaluate the functionality of these cells,
