EFFECTS OF THE SEX RATIO ORGANISM ON IN VITRO DIFFERENTIATION OF DROSOPHILA EMBRYONIC CELLS

Effects of Sex Ratio Organism (SRO) on the development of embryonic cells of Drosophila melanogaster were studied in vitro. The single embryo culture technique and a histochemical staining method were employed to distinguish male embryo cultures from female ones. SRO-infected Zw(n) females were crossed to wild-type males, and their embryos were separately dissociated and cultured in vitro. Cell growth and differentiation in each culture were examined by phase contrast microscopy and described both qualitatively and quantitatively. Neurons, imaginal disk cells and plasmatocyte-like cells barely differentiated in male (Zw( n)/Y) cultures, whereas muscle and fatbody cells were not so severely affected. These symptoms were generally specific to male cultures. Female (Zw(n)/+) cultures were relatively normal. These observations are consistent with the results of mosaic analysis. The susceptibility of cells to SRO is discussed in relation to the dose of X chromosome in the cells.