A two compartment model of hematopoiesis. Hematopoietic stem cells have three possible fates: replication (self-renewal), which occurs with intensity λ_R ; the initiation of a differentiation/maturation program, which occurs with intensity μ_R ; and apoptosis, which occurs with intensity α_R . Hematopoiesis was simulated assuming all determinations were determined by chance. Progenitor cells (BFU-E and CFU-GM) are sampled from the contributing clone compartment each 4 weeks for 6 years to mimic feline studies.