Paternal mtDNA transmission

In genetics, paternal mtDNA transmission and paternal mtDNA inheritance refer to the incidence of paternal mitochondrial DNA (mtDNA) being passed on to offspring. Paternal mtDNA inheritance is observed in a small number of species, but in the vast majority, mtDNA is believed to be passed unchanged [The mtDNA is passed from mother to offspring unchanged except for the occasional genetic mutation, the rate of which is unknown but is sometimes estimated as once every 600 generations (see [http://www.cs.unc.edu/~plaisted/ce/mitochondria.html Mitochondrial DNA Mutation Rates] ).] from a mother to her offspring.

In animals

Paternal mtDNA inheritance in animals varies. For example, in Mytilidae mussels, paternal mtDNA "is transmitted through the sperm and establishes itself only in the male gonad." [ [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11280005&dopt=Abstract The exceptional mitochondrial DNA system of the mussel family Mytilidae] by E. Zouros, December 2000.] [ [http://www.genetics.org/cgi/content/full/148/1/341 The Fate of Paternal Mitochondrial DNA in Developing Female Mussels, "Mytilus edulis": Implications for the Mechanism of Doubly Uniparental Inheritance of Mitochondrial DNA] by Brent Sutherland, Donald Stewart, Ellen R. Kenchington, and Eleftherios Zouros] [ [http://mbe.library.arizona.edu/data/1995/1205/3stew.pdf Male and Female Mitochondrial DNA Lineages in the Blue Mussel "(Mytilus edulis)" Species Group] by Donald T. Stewart, Carlos Saavedra, Rebecca R. Stanwood, Amy 0. Ball, and Eleftherios Zouros] In testing 172 sheep, "The Mitochondrial DNA from three lambs in two half-sib families were found to show paternal inheritance." [ [http://www.nature.com/hdy/journal/v93/n4/full/6800516a.html Further evidence for paternal inheritance of mitochondrial DNA in the sheep (Ovis aries)] by X. Zhao1, N. Li, W. Guo1, X. Hu, Z. Liu, G. Gong, A. Wang1, J. Feng and C. Wu1, "Nature", October 2004, Volume 93, Number 4, Pages 399-403]

Mitochondria in mammalian sperm are usually destroyed by the egg cell after fertilization. In 1999 it was reported that paternal sperm mitochondria (containing mtDNA) are marked with ubiquitin to select them for later destruction inside the embryo [Sutovsky "et al." 1999)] . Some "in vitro" fertilization techniques, particularly injecting a sperm into an oocyte, may interfere with this.

In humans

Many sources, notably companies that sell genealogical DNA tests, state that paternal mtDNA is never transmitted to offspring. This belief is central to mtDNA genealogical DNA testing and to the theory of mitochondrial Eve.POV-statement|date=February 2008 However, there have been some studies that claimed to have found some cases of paternal mitochondrial inheritance in humans (e.g. Schwarz & Vissing 2002), and it was proposed that in sexual reproduction, the tail of the sperm does enter the egg, and thus "paternal leakage" may occur.Fact|date=July 2007

The ideas about human paternal leakage were summed up in the 1996 study "Misconceptions about mitochondria and mammalian fertilization: Implications for theories on human evolution": [ [http://www.pnas.org/cgi/content/full/93/24/13859 Misconceptions about mitochondria and mammalian fertilization: Implications for theories on human evolution] by Friderun Ankel-Simons and Jim M. Cummins, 1996] Verify credibility|date=February 2008

The mixing of maternal and paternal mtDNA was thought to have been found in humans and chimpanzees. [ [http://www.lifesci.sussex.ac.uk/CSE/members/aeyrewalker/pdfs/AwadallaScience99.pdf Linkage Disequilibrium and Recombination in Hominid Mitochondrial DNA] (PDF) by Philip Awadalla, Adam Eyre-Walker, and John Maynard Smith, (view [http://www.sciencemag.org/cgi/content/abstract/286/5449/2524 abstract] ), "Science", 24 December 1999: Vol. 286] [ [http://www.sciencemag.org/cgi/content/summary/286/5449/2436a mtDNA Shows Signs of Paternal Influence] by Evelyn Strauss, "Science", 24 December 1999: Vol. 286. no. 5449, p. 2436; DOI: 10.1126/science.286.5449.2436a] However, there has been only a single possible case of human paternal mitochondrial DNA transmissionFact|date=July 2007. All other reported cases can be ascribed solely to contamination and sample mix up.

Responses to this evidence involves saying that so little paternal mtDNA is transmitted as to be negligible ("Some researchersFact|date=February 2008 argue that a fragment of the father's mtDNA is in fact passed on, though it represents much less than 1 percent of the total." [ [http://www.pbs.org/wgbh/nova/teachers/activities/3116_stoneage.html NOVA Teachers: America's Stone Age Explorers Classroom Activity] ] Verify credibility|date=February 2008) or saying that paternal mtDNA is so rarely transmitted as to be negligible ("Nevertheless, studies have established that paternal mtDNA is so rarely transmitted to offspring that mtDNA analyses remain valid..." [evolutionary biologist Andrew Merriwether quoted in [http://www.highbeam.com/library/docfree.asp?DOCID=1G1:19084154 Debunking a myth about sperm's DNA. (research indicates paternal mitochondrial DNA does enter fertilized egg)] by John Travis, Science News, 1/25/1997] ). It has also been said in early studies that about 1-2% of a person's mitochondria can be inherited from the father ["Mitochondria can be inherited from both parents", New Scientist article on Schwartz and Vissing's report; [http://www.newscientist.com/news/news.jsp?id=ns99992716] . The report is: cite journal | author=Marianne Schwartz and John Vissing | title=Paternal inheritance of mitochondrial DNA | journal=New England Journal of Medicine | year=Aug 22, 2002 | pages=576–80 | volume=347 | issue=8 | pmid=12192017 | url=http://www.life.uiuc.edu/csb/213/PDF/mitochondria.pdf | doi=10.1056/NEJMoa020350|format=PDF] .

According to the 2005 study "More evidence for non-maternal inheritance of mitochondrial DNA?": [cite journal | author= Bandelt HJ, Kong QP,Parson W, and Salas A.
title=More evidence for non-maternal inheritance of mitochondrial DNA? | journal=American Journal of Medical Genetics | date=May 27, 2005 | pages=957–60 | volume=42 | issue=12 | pmid=15923271 | url=http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=15923271&query_hl=11&itool=pubmed_docsum] In addition, heteroplasmy is a "newly discovered form of inheritance for mtDNA. Heteroplasmy introduces slight statistical uncertainty in normal inheritance patterns." [ [http://www.rastafarispeaks.com/cgi-bin/forum/archive0/config.pl?noframes;read=7818 Re: Most-recent common ancestor] ] Heteroplasmy occurs when two slightly different mitochondrial sequences are inherited from the mother, as a result of several hundred mitochondria being present in the ovum.

On the other side of the issue are people who want to dismiss maternal mtDNA inheritance completely. A surname project tutorial states, "A male will rarely get his father's mtDNA. So far, this has been observed one time in the past 20 years of research." [ [http://jordannctoal.homestead.com/JordanDNATutorial.html Jordan Surname DNA Project: Tutorial] ] Verify credibility|date=February 2008 This single instance is cited as evidence that the whole field of human mitochondrial genetics is invalid.Fact|date=August 2007

In either case, these phenomena throw doubt on the theory that all mtDNA can be traced back to a single female.POV-statement|date=February 2008 This theory of mitochondrial Eve, which aims to trace all humans to "a woman living in sub-Saharan Africa about 200,000 years ago" [ [http://www.abbottloop.org/alconweb/i_c_r/afrieve.htm African Eve Theory Smashed by Computer] by Marvin Lubenow, July 1992] allows no room for the inheritance of paternal mtDNA.

In protozoa

Some organisms, such as "Cryptosporidium", have mitochondria with no DNA whatsoever.

In plants

It has also been reported that mitochondria can occasionally be inherited from the father, e.g. in bananas. Some Conifers also show paternal inheritance of mitochondria, such as the coast redwood, "Sequoia sempervirens".

References and notes

ee also

*Y-chromosomal Adam
*Patrilineality
*Matrilineality
*Human mitochondrial genetics
*Human migration
*RecLOH
*List of genetic genealogy topics

External links

* [http://molehr.oxfordjournals.org/cgi/content/abstract/8/11/1046 No evidence for paternal mtDNA transmission to offspring or extra-embryonic tissues after ICSI] by D.R. Marchington, M.S.G. Scott Brown, V.K. Lamb, R.J.T. van Golde, J.A.M. Kremer, J.H.A.M. Tuerlings, E.C.M. Mariman, A.H. Balen and J. Poulton
* [http://www.journals.uchicago.edu/AJHG/journal/issues/v66n5/991452/991452.text.html?erFrom=-108519787244176182Guest The Mutation Rate in the Human mtDNA Control Region] by Sigrún Sigurðardóttir, Agnar Helgason, Jeffrey R. Gulcher, Kári Stefansson, and Peter Donnelly
* [http://brain.oxfordjournals.org/cgi/content/abstract/127/10/2153 Mitochondrial disorders] by Massimo Zeviani and Stefano Di Donato
* [http://www.blackwell-synergy.com/links/doi/10.1046%2Fj.1439-0531.2003.00448.x The Mitochondrial Genome in Embryo Technologies] by S Hiendleder and E Wolf
* [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?term=Barr+Neiman+Taylor&sourceid=mozilla-search&db=PubMed&orig_db=PubMed&dispmax=20&dopt=DocSum Inheritance and recombination of mitochondrial genomes in plants, fungi and animals] ( [http://www.people.virginia.edu/~drt3b/publications/neimanMaurine/Barr_et_al2005.pdf PDF] ) by Camille M. Barr, Maurine Neiman and Douglas R. Taylor, 2005
* [http://molehr.oxfordjournals.org/cgi/content/abstract/8/11/1046 No evidence for paternal mtDNA transmission to offspring or extra-embryonic tissues after ICSI] by D.R. Marchington, M.S.G. Scott Brown, V.K. Lamb, R.J.T. van Golde, J.A.M. Kremer, J.H.A.M. Tuerlings, E.C.M. Mariman, A.H. Balen and J. Poulton
* [http://www.life.uiuc.edu/csb/213/PDF/mitochondria.pdf Paternal inheritance of mitochondrial DNA] (PDF) by Marianne Schwartz and John Vissing, 2002
* [http://www.springerlink.com/content/mv5812037q10u886/ Paradise lost: Mitochondrial eve refuted] by M. Pickford, July 2006
* [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed PubMed] :
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** [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=PureSearch&db=pubmed&details_term=%28%28%22humans%22%5BTIAB%5D%20NOT%20Medline%5BSB%5D%29%20OR%20%22humans%22%5BMeSH%20Terms%5D%20OR%20human%5BText%20Word%5D%29%20AND%20mitochondrial%5BAll%20Fields%5D%20AND%20haplogroup%5BAll%20Fields%5D=QuerySuggestion search results for "papers about human mitochondrial DNA phylogenetics"]