Figure 4.

Trajectories of cells. (a) The migration trajectories of cells moving from the bottom of the crypt to the top of the crypt when differential cell adhesion is maintained. (b) The trajectories of cells without differential cell adhesion show that, instead of staying at the bottom of the crypt, the Paneth cell (represented by dark blue dots) moves upwards when there is no differential adhesion. On the other hand, the proliferative cell in (b) stays at the bottom of the crypt and does not move upwards to the top of the crypt. The dot-to-dot distance equals 1 h. The colour of the dot corresponds to the cell type at that time point.