FLT3 ligand is dispensable for steady-state maintenance of adult HSCs. (A) Representative fluorescence-activated cell sorting (FACS) plots for analysis of LSKCD34⁻FLT3⁻ and LSKCD34⁻D150⁺ cells in 9- to 10-week-old WT and Fl^−/− mice. Numbers indicate frequencies of populations within indicated gates or quadrants of total BM cells. Cells have first been gated on Lin⁻ cells as indicated. (B) Mean (SEM) numbers of LSK, LSKCD34⁻FLT3⁻, and LSKCD34⁻CD150⁺ cells in BM (per 2 tibiae and 2 femora) of 9- to 10-week-old WT and Fl^−/− mice (n = 5 per genotype). ns indicates not significant.