Thymocyte and ETP numbers in WT and Foxn1Tg. (A) Thymocyte numbers in 3-month-old, 16- to 19-month-old, and 20- to 26-month-old WT (white bars) and Foxn1Tg (line 60; black bars). P values from comparison between WT and Foxn1Tg as determined by t test or Mann-Whitney are as follows: *P = .043 and **P = .012, respectively. (B) Frequencies of ETP in WT (white bars) and Foxn1Tg (black bars). ETP are defined as Lin⁻ CD117⁺ CD44^hi CD25⁻ C127⁻. WT 3-month-old versus WT 18- to 24-month-old: #P = .009; Foxn1Tg 25- to 36-month-old versus WT 18- to 24-month-old: *P = .038 (P values from t test). (C) Total number of ETP in WT (white bars) and Foxn1Tg (black bars) mice. WT 3-month-old versus 21- to 24-month-old: #P = .003; Foxn1Tg 3-month-old versus 21- to 30-month-old: ##P < .001; Foxn1Tg 21- to 30-month-old versus WT 21- to 24-month-old: *P = .047 (P values from t test). Error bars represent SD. Values in parentheses represent the number of mice in each group. Data were from line 5 and line 60.