HSC composition of the bone marrow after secondary transplantation of control (left) and double Dnmt3a/3b KO (right) HSCs. After control HSC transplantation, HSCs comprise ∼0.01% of whole bone marrow. After transplantation of dKO HSCs, phenotypically-defined HSCs (KLS CD34–Flk2–) comprise ∼0.48% of bone marrow.