[Determination of a temperature-sensitive period of the new mutation lawc(P1) in Drosophila melanogaster].

Determination of the period of temperature sensitivity in the temperature-sensitive allele of the regulatory lawc(P1) mutation was performed. Homeotic transformation of arista into tarsus, frequency of leg deformation, and bristle superexpression were examined. The sensitive periods were detected using reciprocal changes of cultivation temperature from 28 to 17 degrees C and from 17 to 28 degrees C. The temperature-sensitive period (TSP) for arista transformation was shown to manifest polyphasic expression and sexual dimorphism. In females, it occurred in late third instar larvae (the first phase) and prepupae (the second stage); in males, it includes the whole period from the late third instar larva upto and including prepupa. TSP for the frequency of deformed legs was polyphasic and took place during the third larval instar (the first phase) and prepupa stage (the second one). TSP for bristle superexpression occurred during a single interval from the late third larval instar until the early prepupa stage. The products of the lawc gene are assumed to play a role both in the cell proliferation in the legs of antennal and imaginal discs and in the control of bristle expression at the final stages of Drosophila ontogeny.