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#sperm mitochondria

2 public questions tagged with this topic.

Fertilization in mammals-l

Post-fertilization sperm mitochondria:

Upon gamete fusion paternal mitochondria located in sperm midpiece enter oocyte cytoplasm along with nucleus and flagellum. Despite entry, sperm mitochondria are targeted for destruction by ubiquitination and mitophagy machinery within early embryo, including recognition by Parkin and LC3 autophagy pathways. Degradation ensures maternal inheritance of mitochondrial genome preventing heteroplasmy and potential incompatibility. By blastocyst stage paternal mtDNA undetectable. This selective elimination explains almost exclusive maternal mitochondrial transmission across generations, with implications for mitochondrial disease inheritance, evolutionary tracking, uniparental inheritance patterns, mitochondrial replacement therapies and genetic counseling paradigms.

Ref: Sato & Sato, Curr Biol: Selective autophagy and elimination of paternal mitochondria ensures maternal inheritance.

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Fertilization in mammals-iv

Sperm mitochondria in mammals:

Paternal mitochondria enter oocyte cytoplasm at fertilization localized in midpiece, but they are actively eliminated shortly thereafter to ensure maternal uniparental mitochondrial inheritance. Ubiquitination of sperm mitochondrial proteins, recognition by oocyte autophagy machinery, mitophagy and proteasomal degradation remove them before first cleavage divisions. Occasionally low-level paternal mtDNA leakage occurs but is exceptional. Therefore mitochondria do not persist, merge or form embryonic population; embryonic mitochondria derive entirely from oocyte pool amplified during oogenesis, supporting high ATP demand of early development while avoiding heteroplasmy conflicts and protecting mitochondrial genome integrity.

Ref: NCBI, Mitochondrial inheritance review: Ubiquitin-mediated paternal mitochondria degradation and mitophagy after mammalian fertilization.

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