Sort strategy for the isolation of nucleated erythroid and CD34⁺ progenitor cell subpopulations. All dot plots are derived from low-density PB cells. Gates for the nucleated erythroid cell population were set to exclude dead (PI⁺) cells (A; gate R1), events appearing in the last channels of forward light and side scatter (B; gate R3) and CD34⁺ cells (D; gate R7). A nucleated erythroid cell (NEC) gate was set to include 99% of the CD71/glycophorin-A⁺ events and cells expressing low to intermediate levels of CD45 (C; gate R4). CD34⁺ hematopoietic progenitor cells were selected on the basis of viability (A; gate R1), low forward and orthogonal light scatter (B; gate R2), low to intermediate levels of CD71 and glycophorin-A, intermediate levels of CD45 (C; gate R5), and high levels of CD34 (D; gate R6).