[A new allele variant of ssa and its participation in regulating the proliferation of the stem elements of the leg and antenna imaginal disks in Drosophila melanogaster].

Using a highly mutable FM/w oc system, we have established a new allele of ssa40aSc mutation whose phenotype is identical to ssa40aNs compound described in the literature. The following features are characteristic of the ssa40aSc flies phenotype: (1) the increased number of sex comb teeth, (2) complete fusion of tarsal segments, and (3) the decreased bristle size corresponding to that of ss flies. The first two features are evidence for the impaired stem cell proliferation in the antennal and leg imaginal discs which are determined to form distal structures. This assumption was experimentally confirmed when we transplanted leg imaginal discs from III instar larvae of different age into prepupae. The observed phenomenon is probably due to the defects of the Antp and Pc translation products binding site in the ss locus.