Similar reconstitution of split bone marrow from individual mice in pairs of secondary transplant recipients. Peripheral blood samples from pairs of secondary mice that received a transplant of bone marrow from identical donors were analyzed by FACS at monthly intervals. Kinetics (A) and differentiation (B) of GFP⁺ blood cells were similar in pairs of secondary mice receiving bone marrow from the same donor. In panel A, time points in months are indicated by successive bars. In panel B, successive bars indicate the proportion of erythroid progenitors, granulocytes, macrophages, B lymphocytes, and T lymphocytes of the GFP⁺ blood cells 12 weeks after transplantation. Representative pairs of secondary mice with (mice 1 a,b, 2 a,b, 4 a,b) or without BCNU/O6BG treatment (mice 3 a,b, 5 a,b) are shown.