Lymphoid- and B-lineage–related genes appear in CD34⁺/CD19⁻ subpopulations and are highly expressed in IL-7Rα⁺ progenitors. Sorting experiments were performed to isolate four sequential progenitor subpopulations with increasing lymphoid potential, representing populations containing no CFU-TdT (a), early CFU-TdT lacking differentiation potential (b), IL-7Rα⁺ CFU-TdT (c), and pro-B cells (d). For clarity, only the early B-lineage markers CD10 and CD19 are listed in the figure among the lineage markers used, which included CD10, CD19, CD20, CD11c, and CD5. The indicated quantity of cDNA (cell equivalents based on the original number of cells sorted) was used as template in the nested PCR reaction. For each gene, results of replicate experiments on a total of two to four separate bone marrow samples were similar to the representative experiments shown, except where noted in the text.