What is "pole cell"

In early Drosophila development, the first 13 passes through mitosis are nuclear divisions (karyokinesis) without cytokinesis, resulting in a multinucleate cell (generally referred to as a syncytium, but strictly a coenocyte). The first mononucleate cells are created at the posterior pole, where the polar granules are tethered. These cells are called pole cells, and they will form the fly's germ line.