Erythroid colony formation from the DiI⁺ cells. (A) Appearance of an erythroid burst formed from the sorted DiI⁺ cells. Original magnification, × 100. (B) RT-PCR analysis for the expression of βH1 and β-major globin gene by the sorted DiI⁺ cells (lane 1) and the erythroid bursts formed from the DiI⁺ cells (lanes 2 to 4). YS indicates 8.5-dpc YS cells; BM, adult bone marrow cells.