Abstract: | A phenogenetic study was carried out of the eyD-mutation in Drosophila melanogaster which reduces the eye and quantitatively affects different regions of the head capsule originating from the eye imaginal disc. It was shown that the change in eye size is connected causally with changes in certain regions of head capsule: increase in chaetae number or duplication in different regions of the head capsule may be due to the degeneration of presumptive ommatidia. It is supposed that the variable response of chaetae number to the decrease in eye size depends on the origin of chaetae and their topography at different stages of the disc development. |