Embryonic MEPs coexpress erythroid and megakaryocytic genes. (A) Relative expression levels of 12 genes as assessed by quantitative RT-PCR. Genes were classified according to their restricted expression in the erythroid (EPOR and KLF1) or megakaryocytic (AML1, FLI1, GABPA, and MPL) lineages (top panel). The second group was composed of genes common to the 2 types of differentiation (GATA1, NFE2, TAL1, GATA2, MYB, and LMO2). Relative expression levels (fold change) of GPA⁺CD41⁺ (MEP) and GPA⁻CD41⁺ (MK) cells were reported to the expression levels measured in the GPA⁺CD41⁻ (Ery) population. Values represent the mean ± SEM of at least 3 independent experiments. Details of the protocol for this analysis are specified in “Single-cell quantitative real-time PCR.” *Significant difference (P < .05). (B) Relative expression levels of MYB, GATA2, LMO2, and KIT transcripts in embryonic MEP versus cord blood and adult progenitor cells (CD34⁺CD41⁺CD42⁻). Values were reported to expression levels found in the adult CD34⁺CD41⁺CD42⁻ fraction and represent the mean ± SEM of at least 3 independent experiments.