DETERMINATION OF THE TEMPERATURE-SENSITIV E PERIOD OF A NEW MUTATION LAWC(P1) IN DROSOPHILA-MELANOGASTER

Determination of the period of temperature sensitivity in the temperat ure-sensitive allele of the regulatory lawc(P1) mutation was performed . Homeotic transformation of arista into tarsus, frequency of leg defo rmation, and bristle superexpression were examined. The sensitive peri ods were detected using reciprocal changes of cultivation temperature from 28 to 17 degrees C and from 17 to 28 degrees C. The temperature-s ensitive period (TSP) for arista transformation was shown to manifest polyphasic expression and sexual dimorphism. In females, it occurred i n late third instar larvae (the first phase) and prepupae (the second stage); in males, it includes the whole period from the late third ins tar larva upto and including prepupa. TSP for the frequency of deforme d legs was polyphasic and took place during the third larval instar (t he first phase) and prepupa stage (the second one). TSP for bristle su perexpression occurred during a single interval from the late third la rval instar until the early prepupa stage. The products of the lawc ge ne are assumed to play a role both in the cell proliferation in the le gs of antennal and imaginal discs and in the control of bristle expres sion at the final stages of Drosophila ontogeny.