Interestingly, the same hematopoietic tendency was observed independently in EBs derived from donor T42 and T55. Global gene expression patterns showed 7- to 16-fold upregulation of embryonic and fetal hemoglobin gene expression (HBE1, HBA2, HBG1, and HBG2) in EBs derived from T42 in comparison with T55. Elevated fetal hemoglobin production has been associated with a reduced total number of circulating erythrocytes in DBA patients (Alter, 1979) and a group of disorders called hereditary persistence of fetal hemoglobin (Forget, 1998). Moreover, of the 66 genes present in the DBA gene set noted above, a total of eight of these were maintained as differentially expressed in the EB stage in donor T55 compared with T42: CASP6, CNOT8, IFT74, LSM5, LYPLA1, PFDN4, PRSS2, and SPAST. In addition, we observed 1- to 12-fold upregulation of megakaryocyte-specific genes (FLI1, MPL, GP9/CD42a, CD36, ITGA2B/CD41) and a 2- to 30-fold upregulation of myeloid lineage genes (MPO, CSF1R, SPI1, CSF3R) in EBs derived from T42 compared with T55 (Figures S6D–S6F).
