Mixed bone marrow chimeras show dominant effect of the IL-7Rα Tg cells on the size of the reconstituted thymus. (A) Thymic cell counts are shown for BM chimeras reconstituted with 100% wild-type, 100% D4, 100% B1, or a 50:50 mixture of wild-type and Tg BM 6 weeks after reconstitution. Error bars represent SEM. (B) The pooled results of multiple experiments in which reconstitution was examined in mixed chimeric animals from 4 to 7 weeks after BM transfer. The black columns represent the percent reconstitution by wild-type thymocytes, and the white columns represent percent reconstitution by IL-7Rα Tg thymocytes. Error represent SEM. (C) B1 IL-7Rα Tg mice were crossed to IL-7 Tg mice, and representative F1 animals from that breeding are shown. Error bars represent SEM.