Cell competition

It is self-evident that cell–cell interactions play important roles in multicellular organisms. Genetic mosaics and chimeras, containing cells of distinct genotypes, have long provided an important way to identify and study these interactions. Beginning in the 970s, genetic mosaic studies in Drosophila began to reveal an unexpected and intriguing phenomenon called ‘cell competition’, in which otherwise viable cells could be eliminated if their neighbors were different (Figure ). Cell competition suggests that the properties of individual cells are monitored during development and that variant clones of progenitor cells can be favored or eliminated accordingly. Interest is now building in the mechanisms of cell competition, how it may be adaptive, and whether cell competition is involved in cancer and other diseases. In recent years, progress has been made in understanding the mechanisms of cell competition through several approaches, although much still remains to be learned.