VITELLOGENETIC DEFECTS IN HYBRIDS OF THE SPECIES PAIR DROSOPHILA-VIRILIS AND DROSOPHILA-TEXANA

In interspecific matings between the species Drosophila virilis and Dr osophila texana, female sterility can be observed in F-2 backcross fem ales and in F-2 hybrid females. The results presented in this report s how that the female sterility, whenever it exists, is due to preventio n of vitellogenin synthesis in the fat body, but other abnormalities s uch as defects with the hybrid ovaries are not excluded. The observati on that sterility appears among females from backcrosses suggests that incompatibilities between interspecific genes may cause female steril ity even in the presence of a complete habloid genome from one or the other species. Yet, the parallel observation that female sterility app ears only in hybrid females with recombinant chromosomes indicates tha t sterility results when conspecific combinations of genes on the same chromosome are broken by interspecific recombination. (C) 1996 Wiley- Liss, Inc.