Cell number in thymuses at various days after γ‐irradiation. Bcl11b
+/+
mice, left; Bcl11b
KO/+
mice, right. Average cell number in Bcl11b
+/+
mice was 4.0, 1.7, 5.0, 3.9, and 3.2 × 107 cells for unirradiated, 14, 30, 60, and 80 days after irradiation, respectively. Average cell number in Bcl11b
KO/+
mice was 4.7, 2.4, 1.8, 0.97, and 0.89 × 107 cells for unirradiated, 14, 30, 60, and 80 days after irradiation, respectively.