Practice question

Pole cells are earliest identifiable primordial germ cell precursors in Drosophila, formed at posterior pole of syncytial blastoderm via inheritance of germ plasm containing Oskar protein, Vasa, Nanos mRNA and mitochondria. Cellularization incorporates these determinants into cluster of pole cells that detach and migrate through midgut into gonadal mesoderm coalescing into gonad. Genetic ablation of Oskar eliminates pole cells causing sterility while somatic lineages remain intact. They do not contribute to neural, epidermal or muscle soma; they exclusively generate functional gametes, transmitting genomic continuity via preformation rather than epigenetic induction.