ONTOGENY OF DROSOPHILA-MELANOGASTER IN A SYSTEM OF DYSGENIC CROSSES

Three families of mobile elements that induce P-M, H-E, and I-R hybrid dysgenesis in Drosophila melanogaster were activated by crossing flies of different cytotypes. Manifestation of gonadal sterility in F-1 hybrid progeny was dependent on the temperature of development. The systems differed significantly in lethality of F-2 hybrids at various stages of ontogeny (embryos, larvae, pupae, and adult flies). The highest embryo lethality was found in the P-M system at the cleavage stage. In the I-R and H-E systems, the peak of embryonic death corresponded to the stages of blastoderm and organogenesis, respectively. Experimental results are discussed in view of molecular and cytological characteristics of interacting strains and existing hypotheses for regulation of transposition of P, hobo, and I mobile elements.