Compartment (development)

In developmental biology, compartments can be simply defined as separate, different, adjacent cell populations, which upon juxtaposition, create a lineage boundary.^[1] This boundary prevents cell movement from cells from different lineages across this barrier, restricting them to their compartment.^[2] Subdivisions are established by morphogen gradients and maintained by local cell-cell interactions, providing functional units with domains of different regulatory genes, which give rise to distinct fates.^[1] Compartment boundaries are found across species. In the hindbrain of vertebrate embryos, rhombomeres are compartments of common lineage^[3] outlined by expression of Hox genes.^[4] In invertebrates, the wing imaginal disc of Drosophila provides an excellent model for the study of compartments. Although other tissues, such as the abdomen,^[5] and even other imaginal discs are compartmentalized, much of our understanding of key concepts and molecular mechanisms involved in compartment boundaries has been derived from experimentation in the wing disc of the fruit fly.