Fig. 1.

Increased self-renewal of LT-HSCs as a consequence of age. (A) Representative FACS profiles of young and old BM cells showing HPCs and multipotent progenitor cells. (B) BM frequencies of KLS cell subsets from young (n = 16), middle-aged (n = 5), and old mice (n = 17). (C) BM frequencies of donor-derived KLS cell subsets after transplantation of BM from young or old donors into young recipients 4 months posttransplant (n = 4 young, n = 3 old). Recipient mice were transplanted with 5-fold more young cells to approximate stem cell equivalents. Statistically significant differences (P < 0.05) are indicated by ^*. ^** in B indicate statistical significance to both of the other age groups.