Bcl11b-lineage tracing from the embryonic stage (E15.5 d) to adulthood (P8w). Bcl11b + epithelial cells were traced from embryonic day 15.5 (E15.5 d). When these offspring reached 8 weeks of age (P8w), their mammary glands were harvested for tdTomato-labeling analysis. j1 , j2 Bar graphs showing the percentage of tdTomato-labeled cells in luminal or basal population ( j1 ) and the percentage of luminal or basal cells among the total tdTomato-labeled epithelial cells ( j2 ). Statistical analysis was performed using two-tailed unpaired t -test. Da t a were presented as means ± SEM, n = 5.