[Phases of the effect of the homeotic Walker mutation in the development of Drosophila melanogaster].

In this work, critical ontogenetic stages for wing traits affected by temperature-sensitive mutation Walker (Wk) were determined. The interaction between the Wk gene and some genes responsible for the cell-cycle control was studied. At various ontogenetic stages, the mutants were exposed to 17 degrees C for 12 h, and, at the beginning of oviposition, the fly age was registered. Nine types of wing abnormalities were classified. The temperature treatment during three developmental stages (12-24, 48-60, and 96-108 h) resulted in a decrease in normal wing number and a substantial increase in wing abnormalities. Different morphological types of imaginal disks were revealed: nondifferentiated disks, those lacking the notum region, and those with duplications of wing-forming regions. The allele-specific interaction between Wk and allele v27 of the Klp61F gene was also revealed. We suggest that gene Wk is a high-ranking gene in the system of genetic control of ontogeny, because the Wk mutation is manifested in numerous phenotypic variants both in the control and in the experiment and a complete set of these variants was observed at each developmental stage upon temperature treatment. The pleiotropic effect of the Wk gene on the formation of some Drosophila organs, including eyes and halters which are beyond the scope of this report, is in agreement with this suggestion.