Why sperm contain mitochondria

Scientists have found a clue to why one type of DNA is passed down to children by their mothers — but not their fathers. DNA inside energy-producing organelles called mitochondria Science. A protein called CPS-6 cuts apart the mitochondrial DNA in the male sperm so that the DNA can’t make the proteins that the mitochondria need to power the cell. Lingering paternal mitochondrial DNA might hurt developing embryos, the researchers say. “This is a very long-standing mystery in biology — why in so many organisms, [only] the maternal mitochondria are inherited,” says Ding Xue, a geneticist at the University of Colorado Boulder who led the work. Millions of years ago, mitochondria were their own simple cells. Now they produce energy for more complex cells, but they’ve held on to their own genomes. Their DNA is simpler and shorter than the regular DNA found in the nucleus of the cell. Xue and his collaborators used electron microscopes to watch as sperm from the worm Caenorhabditis elegans fertilized eggs. The images showed the paternal mitochondria breaking down from the inside out. To figure out what gene might be responsible, the researchers then looked at what changed when certain genes weren’t working. The culprit gene they identified produces the protein CPS-6. CPS-6 normally controls a process of programmed cell death that helps organisms keep old cells and new cells in balance. But Xue’s team found that during fertilization, CPS-6 could also move into the innermost part o...

BACKGROUND The best-known role of spermatozoa is to fertilize the oocyte and to transmit the paternal genome to offspring. These highly specialized cells have a unique structure consisting of all the elements absolutely necessary to each stage of fertilization and to embryonic development. Mature spermatozoa are made up of a head with the nucleus, a neck, and a flagellum that allows motility and that contains a midpiece with a mitochondrial helix. Mitochondria are central to cellular energy production but they also have various other functions. Although mitochondria are recognized as essential to spermatozoa, their exact pathophysiological role and their functioning are complex. Available literature relative to mitochondria in spermatozoa is dense and contradictory in some cases. Furthermore, mitochondria are only indirectly involved in cytoplasmic heredity as their DNA, the paternal mitochondrial DNA, is not transmitted to descendants. SEARCH METHODS PubMed was used to search the MEDLINE database for peer-reviewed original articles and reviews pertaining to human spermatozoa and mitochondria. Searches were performed using keywords belonging to three groups: ‘mitochondria’ or ‘mitochondrial DNA’, ‘spermatozoa’ or ‘sperm’ and ‘reactive oxygen species’ or ‘calcium’ or ‘apoptosis’ or signaling pathways’. These keywords were combined with other relevant search phrases. References from these articles were used to obtain additional articles. OUTCOMES Mitochondria are central to ...

The ancestor of all mitochondria is a type of bacterium that was swallowed by another bacterium, and this monstrous creature gave rise to the eukaryotes. A eukaryote is any organism whose cells contain a nucleus and other organelles enclosed within membranes - so all plants, animals, and fungi alive today.

Bachelor's Degree in Biotechnology from the Technical University of Valencia (UPV). Biotechnology Degree from the National University of Ireland en Galway (NUIG) and embryologist specializing in Assisted Reproduction, with a Master's Degree in Biotechnology of Human Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI) Embryologist. Bachelor's Degree in Biotechnology from the Technical University of Valencia (UPV). Biotechnology Degree from the National University of Ireland en Galway (NUIG) and embryologist specializing in Assisted Reproduction, with a Master's Degree in Biotechnology of Human Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI) License: 3185-CV. We use our own and third party cookies that provide us with statistical data and your browsing habits; with this we improve our content, we can even show advertising related to your preferences. If you want to disable these cookies click the Configure button. To keep all these cookies active, click the Accept button. More information on the Necessary cookies are absolutely essential for the website to function properly. These cookies ensure basic functionalities and security features of the website, anonymously. Cookie Duration Description _lscache_vary 2 days Allows Litespeed Server to store configurations to improve web performance cookielawinfo-checkbox-analytics 11 months This cookie is set by GDPR Cookie Consent plugin. The ...

Buy or subscribe The DNA of eukaryotic organisms (such as animals, plants and fungi) is stored in two cellular compartments: in the nucleus and in organelles called mitochondria, which transform nutrients into energy to allow the cell to function. The nucleus harbours most of our genes, tightly packaged into 46 chromosomes, of which half are inherited from our mother’s egg and half from our father’s sperm. By contrast, mitochondrial DNA (mtDNA) was thought to derive exclusively from maternal egg cells, with no paternal contribution Proceedings of the National Academy of Sciences, Luo et al. • Hutchison, C. A. III, Newbold, J. E., Potter, S. S. & Edgell, M. H. Nature 251, 536–538 (1974). • Luo, S. et al. Proc. Natl Acad. Sci. USA 115, 13039–13044 (2018). • Hecht, N. B., Liem, H., Kleene, K. C., Distel, R. J. & Ho, S. Dev. Biol. 102, 452–461 (1984). • Sager, R. & Lane, D. Proc. Natl Acad. Sci. USA 69, 2410–2413 (1972). • Nishimura, Y. et al. Proc. Natl Acad. Sci. USA 103, 1382–1387 (2006). • Holt, I. J., Harding, A. E. & Morgan-Hughes, J. A. Nature 331, 717–719 (1988). • Gorman, G. S. et al. Nature Rev. Dis. Primers 2, 16080 (2016). • Hauswirth, W. W. & Laipis, P. J. Proc. Natl Acad. Sci. USA 79, 4686–4690 (1982). • Shoubridge, E. A. Hum. Reprod. 15 (Suppl. 2), 229–234 (2000). • Schwartz, M. & Vissing, J. N. Engl. J. Med. 347, 576–580 (2002). • Wallace, D. C. et al. Science 242, 1427–1430 (1988). • Huber, N., Parson, W. & Dür, A. Forens. Sci. Int. Genet. 37, 204–214 (2018). ...