Fig. 4. Colon crypt expansion in Igf2 knockout, wild-type and K:Igf2 mice. (A) Crypt fission rates at 2-4 weeks of age. (B) Proliferative index measured at 2 weeks and 12 weeks of age (K:Igf2 samples indicated by K2). At least 6 crypts were sampled in each animal and the results averaged (medians indicated by horizontal bars, interquartile range by boxes and full range by whiskers); n6 for each genotype tested. Kruskal-Wallis test for significance: 2-week (columns 1-3) P=0.0069; 12-week (columns 4-6) P=0.0293.