Clonally related cells are restricted to organ boundaries early in the development of the chicken gut to form compartment boundaries.

The gut organs are all derived from a simple, undifferentiated, linear gut tube. We analyzed the lineage relationships of cells derived from this gut tube in chicken embryos, determining where the progeny of a single cell are located within the gut. We find that daughter cells derived from a single progenitor can populate both the gizzard (chicken stomach) and the small intestine early in development, but that clonally related cells are restricted to a single organ by stage 12. We also find that clonally related cells can populate different mesodermal layers within the radial axis of the gut throughout all of the stages tested in these experiments. Many genes that have organ-specific expression patterns within the gut have been isolated. The onset of these restricted expression patterns correlates with the time that clonal boundaries appear to form, suggesting that these genes might be involved in the establishment of compartment boundaries, which prevent cells on one side of the boundary from intermingling with cells on the other side of the boundary. Copyright 2000 Academic Press.