Cell clones and pattern formation: Developmental restrictions in the compound eye ofDrosophila.

Five regions of the compound eye have been found to be preferential boundaries for clones of labelledMinute cells, and to act restrictively on the growth of cell clones after a given developmental stage. One of these regions is topographically related to the line of pattern inversion existing at the level of the equator. The results of experiments showing independency of origin of restriction lines and line of pattern inversion are reported.