Simulations of gene therapy in which two marked cells are included among the 300 transplanted HSCs. Marked cells have one-half the chance of differentiation as unmarked HSC. In this circumstance, marked clones often dominate hematopoiesis, sometimes requiring 250 weeks from transplantation, however. The kinetics by which labeled hematopoietic stem cells dominate hematopoiesis are shown in (B). Column 1 shows the kinetics of the outcome seen in experiment a1 of (A). Marked clones first dominated the hematopoietic stem cell reserve, and then the contributing clone compartment. The last two rows of column 1 shows this effect in terms of the number of marked (solid line) and unmarked (dotted line) cells within the hematopoietic stem cell reserve, and the number of marked and unmarked clones contributing to hematopoiesis, respectively. Column 2 presents the additional data from experiment b2 of (A) and shows a similar kinetics.