The hereditary ovarian tumors of the fes mutant of Drosophila melanogaster

Abstract

Hereditary ovarian tumors occur in female Drosophila melanogaster homozygous for the recessive, second chromosomal gene female-sterile (fes). Cells within tumorous ovaries of certain ages can differentiate into cells which, on the basis of their chromosomal morphology, resemble normal nurse cells. There is a positive correlation between the frequency of this more normal differentiation and the degree to which the residual genotype is heterozygous. Flies whose residual genotype is most heterozygous also produce the largest number of non-tumorous chambers. Such chambers, however, generally contain subnormal numbers of nurse cells. Vitellogenesis also occurs in the ovaries of such flies, but extremely rarely. Banded, polytene chromosomes are found in the nuclei of some of the larger, nurse-like cells. Various speculations are advanced to explain these observations. The fes gene when homozygous does not confer special growth factor requirements upon the larva.