Ovarian tumors are characteristically found in adult Drosophila melanogaster females homozygous for certain recessive genes (fes, nw and fu). Ovaries genetically destined to become tumorous do so even when they are transplanted to a normal abdomen. Normal ovaries transplanted to the abdomen of females homozygous for such tumor genes do not become tumorous. Therefore there is no evidence for diffusible tumorigenic agents as initiating factors in the development of the ovarian tumors characteristic of females homozygous for fes, nw or fu. Vitellogenesis is retarded in adult females homozygous for certain recessive genes (fs 2.1, ty and ap4). Transplantation of ovaries from homozygous females to the abdominal body cavity of females carrying the + alleles of the gene in question fails to cure the implant in the case of fs 2.1 and ty. Ovaries of ap4/ap4 genotype produce abundant yolk when implanted into wild type abdomens. Thus it is the abdominal environment of ap4 which is at fault, rather than a malfunctioning of the ovary.

King, R. C., & Bodenstein, D. (1965). The Transplantation of Ovaries between Genetically Sterile and Wild Type Drosophila melanogaste. Zeitschrift Für Naturforschung B, 20(4), 292–297.