Primitive Tert^−/− hematopoietic cells express elevated levels of γ-H2AX. Expression of γ-H2AX and DNA content were analyzed by flow-cytometry, within LSK subset of (A) Nonmanipulated WT and Tert^−/− BM. (B) Recipient- (CD45.2⁻) and donor-derived (CD45.2⁺) BM from recipients reconstituted with nonmanipulated WT BM or Tert^−/− BM; (C) Recipient- (GFP⁻) and donor-derived (GFP⁺) BM from recipients reconstituted with NA10hd-transduced and in vitro expanded either WT or Tert^−/− BM cells.