"Cytoplasmic" Sterility in Drosophila paulistorum Which Is Ultimately Dependent on Nuclear Genes

Abstract

A case of hybrid sterility in Drosophila paulistorum is due to an incompatibility of the Y chromosome of certain strains with the cytoplasm of other strains. The constitution of the cytoplasm responsible for the sterility is not, however, independent of the chromosomal genes. After seven backcrosses of the hybrid females to males of the same strain, fertile male progenies are finally obtained.