Asymmetric development and function of paired sperm-storage organs in <em>Drosophila melanogaster</em>

Paired structures often have similar forms and functions, but the processes underlying their formation can differ. They may originate from a common source or from parallel sources, or arise from distinct precursors that follow separate developmental pathways, ultimately converging on comparable structures and roles. When asymmetries emerge and persist through development, members of the pair can specialize in ways that might increase fitness. Here, we report that the Drosophila melanogaster...