TABLE 1.

Prevalence of the reduced crypt number phenotype

Day after first tamoxifen injection	Age of mice (days)	No. of mutant mice with reduced crypt numbers/no. examined
2	9	0/5
4	11	3/4
6	13	8/9
8	15	4/7
10	17	0/2
14	21	0/2
21	28	0/2
90	97	0/3