[Mapping of the focus of action of the lethal allele of the ecslt76 gene using genetic mosaics].

Using gynandromorph the fate map of Drosophila melanogaster blastoderm was constructed. The focus of the lethal allele lt76 of the ecs gene was localised in two map sites. The site localized in the anterior part gives rise to the anterior region of the nervous system, and head. The latter covers the blastoderm anlages which are involved in the development of abdomen, and the genital imaginal disc. Interaction between two systems controlling morphogenesis is under debate.