Fig. 2. Abnormal hair cycling in Msx2 knockout mutant mouse. (A) Hair distribution of the same mouse, pictures taken 1 month apart. Note the dramatically different hair patches. In 1 month, hairy regions became bald, and bald regions became hairy. (B) Asynchronous hair cycle domains in the same mutant mouse over time. Msx2 knockout mice show a cyclic balding pattern. To examine the balding pattern, we followed five mice (1 month old) over an 80-day period, taking photos about once every 3 days. One example is shown here. Hair regrowth first appears in the shoulder region, spreads to the whole trunk, and then starts to get lost from cephalic to caudal end until all hairs are lost. This pattern then repeats. The times when most trunk hairs are in anagen are boxed in red.