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