Talk:Mitochondrial DNA

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Bad Reference
The line: "Mitochondrial DNA can be regarded as the smallest chromosome coding for only 37 genes and containing only 16,500 base pairs." is cited to reference three, which does not contain this information. — Preceding unsigned comment added by 96.19.62.158 (talk) 23:09, 9 December 2012 (UTC)

Another bad reference is found at the end of the paragraph "The low effective population size and rapid mutation rate (in animals)..." under "Use in identification". The reference doesn't seem to contain this information, as it has a different focus than the paragraph has 157.82.243.52 (talk) 04:03, 4 August 2015 (UTC)

Cleanup
I think this article needs a rewrite. At the moment it has very little to say about what Mitochondrial DNA is and how it differs ballsin tracing inheritance. -- Solipsist 09:12, 24 Aug 2004 (UTC)

This should probably go on pages needing attention rather than cleanup.Dunc_Harris|&#9786; 10:24, 24 Aug 2004 (UTC)

I'ved added some stuff but it still doesn't cover half of what is known.Geni 10:39, 24 Aug 2004 (UTC)


 * Thanks. That looks a lot better. Is the information on the number of rings & genes assuming human/mamillian cells? -- Solipsist 14:12, 24 Aug 2004 (UTC)


 * It comes from human but I don't know how much mitacondria differ between speciesGeni 14:15, 24 Aug 2004 (UTC)

This article covers the same territory as the mitochondrial genome page. I suggest that the two articles be merged together. -- Abstraktn 07:44, 17 Jan 2005 (UTC)

I am building a new table of contents with stubs to show where this article vs the one on human mitochondria needs to go.--RebekahThorn 10:52, 1 November 2006 (UTC)

Link to vila's work
The link provided by User:Magnus Manske goes to a page requiring authentication. Can he post the extract instead? -- Sundar 12:20, Sep 22, 2004 (UTC)


 * The link was apparently removed by someone long ago without identifying the work, making the text mention of "Vilà et al" meaningless. I have fixed this by providing a full citation of the implied Science article, "Multiple and Ancient Origins of the Domestic Dog". I am not aware of any free-access link for this article, but that doesn't mean we should delete any reference to it. The important thing is to unambiguously identify the work, whether or not it's available on the web. ~ Jeff Q (talk) 15:34, 5 February 2008 (UTC)
 * I have added the PDF of the Vilà's article (found at consevol.org). Alexcalamaro (talk) 21:24, 3 October 2022 (UTC)

Traits and Consequences
Nothing is said about what traits mitochondrial DNA may affect - surprising, after 10 years now. I found a reference to "Skuder, P., Plomin R., McClearn, G., Smith, D., Vignetti, S., Chorney, M., Chorney, K., Kasarda, S., Thompson, L., Detterman, D., Petrill, S., Daniels J., Owen, M., & McGuffin P. (1995). A polymorphism in mitochondrial DNA associated with IQ? Intelligence, 21, pages 1-12" but was unable to Google other results or traits. (See )

Such traits could have far-reaching consequences. For example, if higher intelligence were linked to mitochondrial DNA, then the plight of women in male-dominated societies would be improved because the way to determine a woman's intelligence is to educate her. (It wouldn't result in one woman being educated and then her sisters being turned into baby mills because regular DNA undoubtedly also plays a role in intelligence.) Simesa 05:12, 8 Jun 2005 (UTC)

More Cleanup
It looks like this article hasn't been touched lately. It definately needs some work. Was this really a featured article at one point? I would say that it should NOT be merged with mitochondrial genetics, but some of the info on that article should be here and not there. Hichris 23:36, 9 December 2005 (UTC)


 * I just checked and it looks like this article was mentioned in a Featured article, but doesn't look like it was one itself. If no one objects in the next few days I'll remove the tags. Hichris 23:39, 9 December 2005 (UTC)

Under "Female Inheritance", the following sentence is currently included: "Most often, the comparison is made to the revised.". This makes no sense to me. What is it that is revised? —Preceding unsigned comment added by 86.143.225.170 (talk) 11:04, 27 October 2009 (UTC)

Thanks for pointing this out. I have just traced the article history way back and found that the 3 missing words are Cambridge Reference Sequence, with a link. They were deleted in an edit dated 18:54 21 Mar 2006. I'll put them back in now. Dirac66 (talk) 14:05, 27 October 2009 (UTC)

Article not to be merged w/ mitochondrial genetics!
I think it would be wise not to merge the articles as mitochondrial genetics is already long, and because so far both articles are limited to human mitochondria and that mitochondrion are much more diverse than that. keeping them separate could alow for an overview of the diversity of mitochondria genomes among species.(specially plants...) AlvarezL 15 Dec 2005


 * There's a lot of duplicacy and irrelevant material in both. Would you like to help? JFW | T@lk  13:33, 15 December 2005 (UTC)

I agree it is rather a case for clean up and sorting info between the two articles than merging. / Habj 17:19, 21 December 2005 (UTC)

It seems "mitochondrial DNA" works as a search term, turns up this article, but not "mitochondrial genetics". This being so, it seems to me sensible to keep the two articles separate but to have them linked? --64.105.73.40 15:26, 20 February 2006 (UTC)

I agree that 'mtDNA' or 'mitochondrial DNA' are the likeliest search terms. This entire discussion is a clear demonstration to me of the folly of relying on Wikipedia for an organized summary of a vast scientific research area like mitochondrial genetics

Conceptus
The original sentance in the opening read, "Virtually 100% of the mtDNA contribution to a conceptus is inherited from the mother." I changed conceptus to zygote, but I was wondering if anyone knew about the origin of the term. Is the word used to try and anthropomorphize a zygote, making it a being instead of a collection of cells for pro-life purposes? Leave me a message if you know; I'm curious if that is the goal. Terry 01:55, 12 May 2006 (UTC)

I don't know who put it there, but conceptus is just a more general term for anywhere between zygote and birth. It may actually be better to leave out a term at all i.e, "Nearly 100% of mtDNA is inherited maternally." Hichris 20:51, 12 May 2006 (UTC)

Deleted and Overwritten Information
Under Paragraph: Origin of mitochondrial DNA Sentence: These two cells are thought to have then entered (ed. ***something's missing here***) forming the first organelle. Oct 10, 2006 11:27

merge from Mitochondrial genome?
Any reason not to merge from Mitochondrial genome? — coe l acan — 21:12, 24 March 2007 (UTC)

I suggest that the "Mitochondrial Genome" entry should contain only the phrase "see Mitochondrial DNA." To the best of my knowledge the two are synonymous. I think I'm agreeing with coelocanth's above statement, although I'm not sure what "merge from" means. If the "Mitochondrial Genome" entry is retained, it needs to be radically changed, since it is poorly written and contains inaccurate generalisations. Paleogene 19:56, 12 September 2007 (UTC)

Slashdot reference.
In a blog article linked on Slashdot, this article's intro was held up as an example of perhaps not the most informative for those who didn't play SimEarth and thus don't know what eukaryotes are.

http://science.slashdot.org/science/07/05/12/158241.shtml

This isn't my area of expertise, but maybe a few more "bare basics" sentences in the intro might help? SnowFire 21:35, 12 May 2007 (UTC)


 * That blog is worth reading carefully The author, Thomas Goetz, used to write for the Wall Street Journal, and left to get an MPH at Berkeley.


 * If I didn't already know what a mitochondrion was, I wouldn't find out from this entry or the mitochondrion entry.


 * Here's an example of what I think is a good example of a clear explanation of a mitochondrion, without talking down and without being inaccessable either, written for an audience that includes medical students (but still too complicated for a lay audience):


 * N Engl J Med. 2003 Jun 26;348(26):2656-68. Mitochondrial respiratory-chain diseases. DiMauro S, Schon EA.


 * More than a billion years ago, aerobic bacteria colonized primordial eukaryotic cells that lacked the ability to use oxygen metabolically. A symbiotic relationship developed and became permanent. The bacteria evolved into mitochondria, thus endowing the host cells with aerobic metabolism, a much more efficient way to produce energy than anaerobic glycolysis. Structurally, mitochondria have four compartments: the outer membrane, the inner membrane, the intermembrane space, and the matrix (the region inside the inner membrane). They perform numerous tasks, such as pyruvate oxidation, the Krebs cycle, and metabolism of amino acids, fatty acids, and steroids, but the most crucial is probably the generation of energy as adenosine triphosphate (ATP), by means of the electron-transport chain and the oxidative-phosphorylation system (the "respiratory chain")


 * Don't feel bad if you can't write like that; the New England Journal of Medicine has some of the best science editors in the world. Nbauman 05:31, 13 May 2007 (UTC)

Can I ask a Candide-like question here?

I am largely ignorant of Biology so an explanation in layman's terms would be appreciated.

I have 32 great great great grandparents :-)

Do I possess genes from ALL of them?

37 genes
Should "consisting of 16,569 base pairs with 37 genes, 13 proteins (polypeptides), 22 transfer RNA (tRNAs) and two ribosomal RNAs (rRNAs)" actually read "consisting of 16,569 base pairs with 37 genes. Those genes code for 13 proteins (polypeptides), 22 transfer RNA (tRNAs) and two ribosomal RNAs (rRNAs)."? Cirbryn 22:39, 29 August 2007 (UTC)
 * Probably -- certainly mtDNA can't consist of proteins etc.--Michael C. Price talk 22:58, 29 August 2007 (UTC)

Mitochondrial DNA coding
Is anything known about the effects of differences in mitochondrial DNA on organisms? Clearly it isn't going to affect skin color or anything of that sort, but it could conceivably have metabolic effects. Perhaps there is so little variation in mitochondrial DNA that its effects are unknown? Andrew 05:44, Apr 9, 2004 (UTC)

Some one should add something about what mitochondrial DNA codes for. —Preceding unsigned comment added by Templemd (talk • contribs) 01:22, 27 October 2007 (UTC)

Organismal Bias
From the title "Mitochondrial DNA" one would reasonably expect to read a general exposition of properties of plant, animal and fungal mtDNAs, and at least a mention of protist mtDNAs (e.g., lots of data on the kinetoplastidae). However, as of this writing the Wikipedia topic is so biased toward animal mtDNA that it should be retitled "Animal Mitochondrial DNA" -- or even "Mammalian Mitochondrial DNA." In writing this I am not advocating such a title change, but urging that information about mtDNAs other than mammalian mtDNA be added. There is plenty of information available on the mtDNAs found in non-vertebrate metazoan groups and in plants, fungi and protists.

The strong bias in this article reflects the equally strong bias that has existed in the mtDNA research community for decades. That bias is understandable - the major source of funding for mtDNA research is and has been medically-oriented granting agencies (e.g., NIH in the USA). However, the topic "Mitochondrial DNA" is inclusive of all organisms that have mitochondria and the information in Wikipedia should be guided by that, and not by research economics. Many of the paradigms and generalizations about animal mtDNA are, in fact, derived solely from studies of vertebrates (primarily mammals) and wholly ignore the large body of data available from studies of other organisms. Mitochondrial genome size, gene content, gene order and obvious inferences about mechanisms of mitochondrial gene expression vary widely, even amongst the metazoa, but this fact is overlooked, ignored or simply unknown to many otherwise very sophisticated investigators. Although I doubt that many who are presently active in mtDNA research will bother to read the mtDNA section in Wikipedia, it is possible that younger students who will become active in mtDNA research in the future might, and it would be good, in my opinion, to give them the realization that many of the dogmatic generalizations about mtDNA, while perhaps true for one organismal group, aren't true for all (or even most). Paleogene 19:57, 12 September 2007 (UTC)

Identification
The sentence "Human mtDNA can be used to identify individuals" seems to contradict a later passage which states that "unlike nuclear DNA mtDNA is not specific to one individual". If mtDNA is not specific to one individual, how can an individual be identified using mtDNA? --128.139.104.49 (talk) 09:45, 28 April 2008 (UTC)

animal mdna
i can find no information about teh standard mdna deviation in animals in wikipedia, we know enough about human mdna for scientific polemics yet apparently this basic fact is nowhere mentioned. it is very relevant for the species topic in the neanderthal discussion, with an average 1 million year life span of a species of higher animal, it could reward promising informations. there must be an average number of mdna sequences in a million year worth specific life. what is it? 15? 24.132.170.97 (talk) 13:42, 17 February 2009 (UTC)

it needs some more photos —Preceding unsigned comment added by 24.67.235.229 (talk) 01:53, 17 February 2010 (UTC)

Reactive Oxygen Species
formed by development from ubiquinone --> semiquinone --> ubiquinol Qh2...

releases and forms other ROS —Preceding unsigned comment added by Avkrules (talk • contribs) 03:50, 6 July 2010 (UTC)

paternal mDNA inheritance
Article states that the paternal mDNA inheritance discovered in a human male was "linked to infertility", but the source does not mention this. It discusses exercise intolerance, not infertility, and states that the cause is a 2-base pair deletion after inheritance, not the paternal transmission itself.

So I've inflicted a 3-base word deletion on the quoted phrase —Preceding unsigned comment added by 75.170.53.17 (talk) 01:33, 1 April 2011 (UTC)

Archaea?
Article states "Nuclear and mitochondrial DNA are thought to be of separate evolutionary origin, with the mtDNA being derived from the circular genomes of the bacteria that were engulfed by the early ancestors of today's eukaryotic cells." Isn't this an assumption that it was bacteria and not archaea that was captured to form the proto-mitochondria organelle?69.237.157.127 (talk) 21:22, 12 June 2011 (UTC)
 * Archaea and eukaryotes are more closely related to each other than to bacteria, based on nuclear DNA. So it's probably based on evidence. -- cheers, Michael C. Price talk 21:35, 12 June 2011 (UTC)
 * Extending the point of M. Price, above... there is extensive evidence based on genomic DNA sequences that mitochondrial DNA is most closely related to a specific family of bacteria, the alphaproteobacteria. Interestingly, these include some of the most invasive bacteria, which might make sense for establishing a stable endosymbiotic relationship. John Mackenzie Burke (talk) 19:42, 14 June 2011 (UTC)

Inheritance in ZW sex-determination system
The article states that mtDNA is inherited from the mother. This is certainly true in organisms that use the XY sex-determination system, such as humans. Logically, it would also hold true in the X0 and haplodiploid systems.

However, what about the ZW system? In that system, the heterogametic sex is the male instead of the female. If mtDNA is inherited in the same way it is in other organisms, the only way mtDNA could possibly be transmitted would seem to be through the male line. In ZW organisms, females can pass either a Z or W chromosome to their offspring, while males can only pass a Z chromosome.

Is there something I'm missing? — Dale Arnett (talk) 15:30, 20 June 2011 (UTC)


 * Never mind. Looks like there is something I'm missing... namely that the chromosomes have nothing to do with it, right? — Dale Arnett (talk) 15:35, 20 June 2011 (UTC)
 * As I understand it, the precise nature of the sex-determination system doesn't matter as much as having motile (or, in the case of X0, absent!) sperm and a sessile ovum. The sperm's mitochondria are jettisoned at the moment of fusion. DS (talk) 04:52, 31 July 2011 (UTC)

inherited by mother in most species??!
While I admit it may seem that way, but I'm sure it's only been proven in a handful of species, and most of them were probably mammals if not vertebrates.

"In most species, including humans, mtDNA is inherited solely from the mother."

They are inherited from the father in honeybees and fruit flies. It seems likely that all hymenopterans and dipterans inherit from the father which between the two consist of over 1/8th of all described species inside themselves. It also may be that all/most insects inherit from the father which alone would change the statement to "In most species, including humans, mtDNA is inherited solely from the father."

I REALIZE this is original research, BUT so is stating that most inherit from the mother. I propose that either the article be changed to reflect this explanation or at least explain that it is only known in the taxa it has been proven it.-- FUNK A MATIC      ~talk   06:58, 5 September 2011 (UTC)

Explaining my edit
The article states— "Mitochondrial DNA can be regarded as the smallest chromosome coding for only 37 genes and containing only 16,569 base pairs."

"16,569" seems excessively precise, and does not state the species. I am sure that the basepair count varies among organisms, and even a bit among individuals in the same species. In fact, this sentence contradicts a later sentence—

"Some plant species have enormous mtDNAs (as many as 2,500,000 base pairs per mtDNA molecule)"

I also changed this sentence—

"Most other DNA present in eukaryotic organisms is found in the cell nucleus."

Not true—in plants, up to 10 percent of the DNA in them consists of chloroplast DNA. Last time I checked, plants are eukaryotes. In addition, multicellular organisms host a myriad of prokaryotic residents, (90% of the cells in the human body are bacterial in fact)—and their DNA is not being counted either.

—Kelvinsong (talk) 23:11, 5 January 2013 (UTC)

Odds of mitochondrial DNA match in unrelated people
I think that this article should state what the probability is of the mitochondrial DNA of two unrelated people, of the same race, or of different races, being identical. Neutrino1200 (talk) 10:29, 1 February 2013 (UTC)

Related move proposal
Talk:MDNA (album) to MDNA In ictu oculi (talk) 14:01, 9 February 2014 (UTC)

Mother = Daughter? What is the significance of an mDNA match?
The question I could not get a clear answer to actually involves a couple of corpses (Egyptian mummies) whose family relationships were being analyzed based on the mitochondrial DNA. I'm pretty sure, but was hoping this article would help me confirm that a match on the mDNA only indicates that the mothers were closely related, NOT that the mother was the same woman. I'm almost sure that's how it works, but I could not find where the article made that clear. In other words, a significant difference in the mDNA would ONLY prove the mothers were NOT the same woman. Shanen (talk) 21:35, 20 January 2018 (UTC)
 * You are right. Two mummies with IDENTICAL mtDNA sequences would share a very recent ancestor along the maternal lineage (this can be the same mother, grandmother, great-grandmother ...). If the mtDNA is significantly DIFFERENT, then the two individuals belonged to different mitochondrial lineages and did not have the same mother. And the greater the differences between the two mtDNA sequences, the older their most recent common ancestor. Manudouz (talk) 09:07, 21 January 2018 (UTC)

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