a "drosophila melanogaster" oocyte develops in an egg chamber in close association with a set of cells called nurse cells. both the oocyte and the nurse cells are descended from a single germline stem cell, however cytokinesis is incomplete in these cell divisions, and the cytoplasm of the nurse cells and the oocyte is connected by structures known as ring canals. only the oocyte undergoes meiosis and contributes dna to the next generation.