[Geographic distribution of 3 types of strains involved in non-Mendelian sterility phenomenon in Drosophila melanogaster].

Crosses between strains of Drosophila melanogaster lead in some cases to F1 females displaying a quite specific kind of incomplete sterility. Such females, (SF female) arise only when females from "reactive" strains are mated with males from "inducer" strains. Crosses in which "neutral" strains are involved, never produce SF progeny. Results show that only inducer flies are found in the wild, while laboratory strains are distributed into the three classes. Moreover we found that this non-mendelian female sterility is quite a common phenomenon, since reactive and neutral strains are presently maintained in the laboratories of many countries.