Screenshots of the current version of the visualization tool. Shown are 2 simulations where a small number of HSCs, 30 (R0 = 30) and the equivalent number of contributing clones that would be present in an aspirate of feline marrow containing 30 HSCs (C0 = 16) are transplanted into a lethally irradiated cat. Fifty percent of the initial transplanted cells are type a (blue) and 50% are type b (green), simulating the autologous transplantation of small numbers of G6PD heterozygous marrow cells as in Abkowitz et al¹²  and Golinelli et al¹⁹ . Observations were plotted every 10 weeks for a 300-week (∼6-year) interval. By the end of the simulation period in panel A, 2878 HSCs are present in the HSC compartment (or HSC reserve); 30.5% are type a. There are also 1337 contributing clones of which 29.5% are type a. Note that the HSC compartment is not yet full at 220 weeks (4 years after this transplantation) as the number of HSCs (N = 2878) is much less than the capacity of the stem cell compartment (K = 10 000 in this simulation). Model parameters, including λ, α, ν, and μ of type a and type b cells, can be independently controlled under the “Advanced” tab (top right). Data are preloaded for cat (shown), mouse, nonhuman primates, and humans, in accordance with Abkowitz et al,³  Catlin et al,⁴  Abkowitz et al,⁵  Shepherd et al,⁷  Guttorp et al,⁹  Abkowitz et al,¹²  Fong et al,¹³  and Becker et al.¹⁴  For cat, the preset value for λ = once per 10 weeks and ν = once per 12.5 weeks (9). The second simulation (B) has identical input parameters as the first simulation (A) but produces a vastly different outcome. Max Cells in Con., maximum cells in contributing compartment.