The heterogeneity of the HSC compartment derives from a limited number of distinct HSC classes. (A) HSC activity in several individual, clonally repopulated mice was followed for 7 months generating 3 segments for each repopulation kinetic. Shown are the percent donor type cells in blood measured at the indicated time points. (B) Distinct subsets of HSCs can be revealed when the repopulation kinetics are classified by symbolic analysis. Similarities between kinetics were quantified by Hamming distance.81 The squares represent the 54 possible HSC groups as defined by the 3 segments of the kinetics and a high (↑) versus low (↓) output of mature cells. Black squares represent the HSC groups actually found. The figures below the square are examples of the HSC subsets actually found. + indicates increase in mature cells over time; −, decrease; and ∼, no change. For details see Sieburg et al.4,81 This research was originally published in Blood.4
