The composition of HSPCs under steady state. (A) Phf6 knockout (KO) mice had higher percentages of pro-B cells in their bone marrow (P = .0429; wild-type, n = 6; Phf6 KO, n = 6). (B) Phf6 KO mice had less GMP (P = .0184; wild-type, n = 11; Phf6 KO, n = 11). (C) Phf6 KO mice had higher percentages of LSK BMCs compared with wild-type mice (P = .0187; wild-type, n = 11; Phf6 KO, n = 11). (D) The percentages of MPP2 were higher in Phf6 KO mice (P = .0035; wild-type, n = 11; Phf6 KO, n = 11). (E) Cell cycle analysis of the subpopulations of Phf6 KO HSPCs exhibited a lower proportion of G0 phase cells compared with the wild-type counterparts. Representative FACS plots showed more active proliferation in Phf6 KO MPP3 compared with the wild-type cells.*P < .05; **P < .01.