DH gene segment use in transplanted sources of hematopoietic precursors. DH gene segment use for sIgM⁺ (A) and sIgM^- (B) cells from adult bone marrow (▪), cord blood (▦), and fetal (□) sources are shown for DH gene use. For adult bone marrow (sIgM⁺, n = 135 + 28; sIgM^-, n = 50 + 49) and cord blood (sIgM⁺, n = 172 + 87 + 112; sIgM^-, n = 87 + 19 + 48) LP sources and one experiment for the fetal LP source (sIgM⁺, n = 173; sIgM^-, n = 51, 2 experiments). DH6 (P = .03 and P = .003) and DH7 (P = .008 and P = .02) in sIgM^- and sIgM⁺ cells were significant for an age-related trend. In addition DH4 (P = .02) in sIgM⁺ and DH3 (P = .01) in sIgM^- cells showed a significant age-related trend. Error bars indicate standard error.