Cellular aspects of gonadal atrophy in P-M hybrid dysgenesis

Gonadal atrophy is the most typical and dramatic manifestation of intraspecific hybrid dysgenesis syndrome leading to sterility of Drosophila melanogaster dysgenic progeny. The P-M system of hybrid dysgenesis is primarily associated with germ cell degeneration during the early stages of Drosophila development at elevated temperatures. In the present study, we have defined the phase of germ cell death as beginning at the end of embryogenesis immediately following gonad formation. The early stages of germ cell formation in dysgenic flies showed sensitivity to developmental temperature increases at any stage of the Drosophila life cycle including the imago. Analysis of germ cell reactions to hybrid dysgenesis induction revealed significant changes in subcellular structure, especially mitochondria, prior to germ cell breakdown. The mitochondrial pathology can be the reason for the activation of cell death pathways in dysgenic germ cells and lead to gonadal atrophy. Summary We investigated the hybrid dysgenesis in the context of germ cell development and observed the dysgenic effect is associated with dramatic pathological changes in structure of germ cell mitochondria and lead to massive and quick cell death. The temperature-dependent screening of germ cells developmental pattern in dysgenic background showed that these cells are susceptible to the hybrid dysgenesis at any drosophila life-cycle stage, including in the imago.