Nebenkern

The Nebenkern is a mitochondrial formation in the sperm of insects such as Drosophila. After the completion of meiosis, spermatid mitochondria wrap around each other to form a spherical aggregate, adjacent to the nucleus. ^[1] The Nebenkern proceeds to elongate into a double-stranded helical structure.^[1][2] During flagellum elongation the Nebenkern unfolds and the two derivatives (major and minor mitochondrial derivatives) elongate down the bundle of microtubules that constitute the core of the flagellum^[3]

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