Spatial patterns of cells in dividing epithelia.

The spatial patterns of cell boundaries in a view of the apical surface of a dividing epithelium are explored by constructing a hypothetical cell pattern of an epithelium of dividing cells. The two elements specified in the hypothetical pattern are the orientation of division planes and the separation between the division planes in neighbouring cells. The orientations of division planes in one generation are all the same but are orthogonal to those in the preceding generation. The division-plane orientations follow in an orthogonal succession, as happens in early embryos. The division planes in neighbouring cells are offset. The contractions of division planes that would occur during cytokinesis distort existing boundaries creating various types of cell shapes. The patterns generated resemble cell patterns found in life. The hypothetical pattern is regenerative and shows how epithelial cell patterns where cells divide might arise. It has enabled the putative identification of sister cells and first cousins in the embryonic chick chorion.