Telomere dysfunction in HSCs and the thymic epithelium has minor effects on the impairment in thymopoiesis. (A-D) Two- to 3-month-old mTerc^+/+ or G3mTerc^−/− recipient mice were lethally irradiated and reconstituted with the bone marrow (1.5 × 10⁶ cells) of 12-month-old G3mTerc^−/− or mTerc^+/+ donor mice (n = 6 recipients per group). At 3 to 5 months after bone marrow transplantation, neonatal thymi from mTerc^+/+ mice or G3mTerc^−/− mice were transplanted under the kidney capsules of the recipient mice. Grafted thymi were analyzed at 2 to 3 months after thymus transplantation. (A) Experimental scheme. (B-D) Analysis of the grafted thymi. The bar graphs show (B) the percentage of CD4 and CD8 double-positive thymocytes, (C) the thymus weight, and (D) the total number of thymocytes. Error bars represent SD in all panels.