Talk:Human mitochondrial genetics

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Timeframe[edit]

From the article: Using these techniques, it is estimated that the first mitochondria (or more correctly, aerobic prokaryote/anaerobic eukaryote symbiotic relationship) evolved, or was consumed, or developed around 10,000,000 years ago.

This makes no sense to me. 10 million years is not nearly old enough for mitochondria, unless I don't understand this statement.


Good catch. (c; The specific source cited in the original paper for that tidbit was:

6. Neuromuscular Disease Center. Washington University, St. Louis, MO; October 10, 2004 [4] (http://www.neuro.wustl.edu/neuromuscular/mitosyn.html#general).

(Don't you just love cited sources?) The site says:

Origin of mitochondria...
Time: 10^7 years ago

This is 10,000,000 in scientific notation, so the paper is accurately reflecting this source.
The question then becomes: which source is right? The Indiana Univ. Purdue site, along with most of google's hits ("http://www.biology.iupui.edu/biocourses/N100/2k2endosymb.html", "http://www.historyoftheuniverse.com/mitochon.html", "http://www.earthlife.net/kingdom.html"), say it is 1.5x10^9 years ago. The Washington Univ. in St. Louis (along with a lone google hit to "http://sun.menloschool.org/~birchler/cells/animals/mitochondria/") says it is 10^7 years ago. The thing is, these sites probably got their information from one another.
I'm leaning toward 10^9, simply because I've always trusted talkorigins.org on this kind of stuff, and that's the date they use. So I'm changing the date, and writing a letter to Indiana University asking for clarification on this point. If they write back explaining that the date meant something else, I'll clarify what I learn in the entry. Otherwise, I think the change is justified. Eric Herboso 20:11, 20 Jan 2005 (UTC)
UPDATE: I sent the webmaster a letter, but I don't know if he's the author or not, nor even if he'll respond. However, I did notice that the website cited its own source as a reference; however, I don't have access to it. If anybody out there subscribes to the New England Journal of Medicine, please check the following article for the 10^7 date. It might be referring to something other than when eukaryotes and mitochondria teamed up together.

Mechanisms of Disease: Mitochondrial Respiratory-Chain Diseases
DiMauro S., Schon E. A.
N Engl J Med 2003; 348:2656-2668, Jun 26, 2003

Eric Herboso 20:48, 20 Jan 2005 (UTC)
10^7 years is definitely wrong regardless of what the source says. It is obviously a typo. The first compartmentalized cells are observed in the fossil record in rocks dated at aprox 1.5^9 years. One could argue these compartments are not mitochondria but rather invaginations of the plama membrane, however, multicellualr organisms appear in the fossil record between 1^9 and 6^8 years so mitochondria have to be in the cells before that time frame. David D. (Talk) 19:57, 4 November 2005 (UTC)[reply]

Mitochondrial genetics[edit]

It would seem that 10.exp7 years is far too short a time span as this would place it well into differentiation of higher life forms ie mammalian, reptilian, and dinosauran divisions.

I agree, surely mitochondria did not just magically pop into existance at that point in time then also-magically appear in all of the eukaryotic life forms. --Miroku Sanna 18:03, 21 July 2005 (UTC)[reply]

Who are the authors???[edit]

Who wrote the article on mitochondria genetics? I'm trying to cite this article as a source, but I'm having troubles. Please help. —The preceding unsigned comment was added by 64.12.116.200 (talk • contribs) .

Wikipedia is written by countless individuals with no special credentials. You can refer to Wikipedia:Citing Wikipedia. JFW | T@lk 20:43, 4 December 2005 (UTC)[reply]

Cleaning Up[edit]

Is the information in the article still safe to use? Is there any information that I should not use for a report. Please answer me as soon as possible!! *<:) —The preceding unsigned comment was added by 64.12.116.200 (talk • contribs) .

Wikipedia is written by random characters, some very well informed and many less so. Hence, I would recommend you fact-check as many details as possible. There has recently been a high-profile case of a journalist relying on Wikipedia without fact-checking and causing disinformation. See the general disclaimer (below) - we provide information, but half may be wrong and you don't know which half :-) JFW | T@lk 20:43, 4 December 2005 (UTC)[reply]

If this article is supposed to be about mitochondrial genetics, then there is lot of unreleated info here that should be removed (e.g. Mitochondrial Membrane Complexes). Even DNA repair and such isn't genetics, it should be included in the mtDNA article but not here. Hichris 04:55, 7 December 2005 (UTC)[reply]

I agree. I've only copyedited the first part, and did not get around to slashing this. JFW | T@lk 20:07, 7 December 2005 (UTC)[reply]

Not Merging[edit]

I am assuming that no one here intends to favor the merger suggests in the main page? I hope not. Most search engines seem not to find this, in a search on "mitochondrial DNA", and t'other way 'round, too. This suggests to me that linking the two articles is better than merging them? --64.105.73.40 16:27, 20 February 2006 (UTC)[reply]

I think the articles (mitochondrial DNA and mitochondrial genetics) should not be merged. However, I do think this article should be renamed to Human mitochondrial genetics and should focus only on humans. -- Reinyday, 23:06, 20 February 2006 (UTC)

This article (which still needs lots of work) already focuses on Human mitochrondrial genetics, so I say go ahead and rename/move it Hichris 19:37, 21 February 2006 (UTC)[reply]

Merge to mitochondrial DNA[edit]

I think that most of this article (70%) belongs in the mitochondrial DNA aritcle, however I think this article with the remaining 30% should stay -- albeit reorganized. Hichris 18:57, 17 July 2006 (UTC)[reply]

I can agree with that. Which 70%?pschemp | talk 20:05, 17 July 2006 (UTC)[reply]
The following sections don't belong here and could be fit into mitochondria DNA article:
"Membrane complexes" (plus the intro paragraph before), "Replication, Repair, Transcription, and Translation", "Mitochondrial Diseases" (perhaps a sentece or two about this, but most mitochondrial diseases are NOT related to the mitochondrial genome.)
Theses sections, perhaps somewhat more concisely, could be merged into the mitochondrial DNA article. Hichris 13:43, 18 July 2006 (UTC)[reply]
Agree with above except the mitochondrial diseases. I thought there were many diseases related to the mitochondrial genome? What makes it fascinating is that due the heteroplasmy (more than one mit genome per cell and both mutant and wild-type) the severity of the disease can be quite variable both heterchronically and tissue specifically. This seems very relevent. Isn't this why Greg LeMond had to retire as his mutant mitochondria started to predominate in his muscle tissues? David D. (Talk) 15:52, 18 July 2006 (UTC)[reply]
MOST mitochondrial disorders are caused by Chromosonal genes, but there are diseases caused by errors in the mitochonrial genome. Mitochondrial myopathy, which Greg LeMond has can be caused (and I believe in his case was) by errors in the mitochondrial genes. So go ahead an keep this section, but should be reworked to explain this better. Hichris 17:43, 18 July 2006 (UTC)[reply]
No doubt it needs reworking and also clarifying the difference between the nuclear and mitochondrial versions of mitochondrial diseases. This is not really my area but i assume one major difference is that the phenotype due to the mitochondrial mutations has variable penetrance as opposed to the diseases in nuclear encoded proteins. David D. (Talk) 17:57, 18 July 2006 (UTC)[reply]
I support keeping Mitochondrial DNA and Human mitochondrial genetics as separate articles, because it would be very tiresome both for the authors and for the reader to always have to distinguish what information is general and what information is human-specific in one single article. Mikael Häggström (talk) 22:16, 12 June 2012 (UTC)[reply]

List of works[edit]

There has been a tag for over two years now urging someone to combine each entry in the "References"-section to corresponding claim in the article, but nothing has happened, and I don't think something will ever happen in this issue. Therefore, I think it's better to remove the list entirely, so that we can start to create a new reference list with wp:in-line citations, because such a list of works is practically worthless without such linking. Mikael Häggström (talk) 21:30, 12 June 2012 (UTC)[reply]

The list of works is as follows:

  1. Roberts D, Frerman F, and Kim J. (December 1996) Three-dimensional Structure of Human Electron Transfer Flavoprotein to 2.1-Å Resolution. Proc. Natl. Acad. Sci. USA. Vol. 93. (dl November 2004).
  2. Naviaux, Robert. (1997) The Spectrum of Mitochondrial Disease. Exceptional Parent Magazine. Vol. 27, Issue 8.
  3. Crofts, Antony R. (1996) Biophysics 354: Biological Energy Conversions. University of Illinois at Urbana-Champaign. (dl November 2004).
  4. Nester, Anderson, Roberts, Pearsall, Nester. Microbiology, A Human Perspective. Boston: McGraw Hill Inc; 2004.
  5. Mitochondrial inheritance tree Mitochondrial DNA genetics
  6. Broughton R, Milam J, and Roe B. (November 2001) The Complete Sequence of the Zebrafish (Danio rerio) Mitochondrial Genome and Evolutionary Patterns in Vertebrate Mitochondrial DNA. Genome Research. Vol. 11, Issue 11. (dl November 2004).
  7. Neuromuscular Disease Center. Washington University, St. Louis, MO; October 10, 2004. (dl November 2004).
  8. Montoya J, Playán A, Alcaine M, Enríquez J, Fernández-Silva P, López-Pérez M, Martinez-Azorín F, Pérez-Martos A. Societat Catalana de Neurologia. Universidad de Zaragoza. (dl November 2004).
  9. United Mitochondrial Disease Foundation. Pittsburgh, PA. (dl November 2004).
  10. Tamarin, Robert H. Principles of Genetics, Seventh Edition. New York, NY: McGraw-Hill Inc; 2002.
  11. Scheffler, Immo E. (2001) Review Article: A Century of Mitochondrial Research: Achievements and Perspectives. Elsevier Science B. V. and Mitochondrial Research Society. (dl November 2000).
  12. Vladutiu, Georgirene D. (1997) Advances in Mitochondrial Disease Research. Exceptional Parent Magazine. Vol. 27, Issue 8.
  13. DiMauro, Salvatore. (1997) Promising Avenues of Investigation in the Diagnosis and Treatment of Mitochondrial Defects. Exceptional Parent Magazine. Vol. 27, Issue 8.
  14. University of Texas Medical Branch. TX; December 2003. The Mitochondrial Life Cycle. (dl November 2004).
  15. The Mitochondrial Research Society. Mitochondria Means the Most to US; 2004. (dl November 2004).
  16. Purves W, Sadava D, Orians G, Heller C. Life: The Science of Biology, Sixth Edition. Massachusetts: Sinauer Associates, Inc; 2002.
  17. Venkatesh S, Deecaraman M, Kumar R, Shamsi MB, Dada R. Role of reactive oxygen species in the pathogenesis of mitochondrial DNA (mtDNA) mutations in male infertility. Indian J Med Res. 2009 Feb;129(2):127-37. Review.

Mikael Häggström (talk) 21:30, 12 June 2012 (UTC)[reply]

Membrane complexes[edit]

I moved the following section (in box below) to here because:

  • It completely lacks wp:references. If someone would find the corresponding references in the list of works above and create wp:in-line citations, then these claims may be reinserted.
  • The article still has several links to Electron transport chain, and a more comprehensive explanation is given there.

Mikael Häggström (talk) 22:13, 12 June 2012 (UTC)[reply]

The processes carried out by the electron transport chain are mediated by protein complexes (named Complexes I-V, DHO-QO, ETF-QO, and ANT). Complex I, or NADH : coenzyme Q oxidoreductase, uses the energy in NADH to pump protons into the intermembrane space of the mitochondrion, pumping 2 protons per electron and passing 2 electrons via coenzyme Q to complex III or coenzyme Q : cytochrome c oxidoreductase. Complex II or succinate : coenzyme Q oxidoreductase accepts energy from succinate produced in the citric acid cycle and passes it via coenzyme Q to complex III. Complex III pumps 1 protons per electron and passes 1 electron via cytochrome c to complex IV or Cytochrome C : O2 Oxidoreductase. Complex IV pumps 1 protons into the space between the mitochondrion’s two membranes before passing the electron to O2 which reacts to form water. Complex V (ATP synthase) is a rotary complex which allows approximately (determining the actual number is very difficult) 10 protons to enter the mitochondrial matrix along their concentration gradients. It uses the energy from the gradient to form the bond between ADP and the phosphate group to create ATP. The electron transfer flavoprotein : coenzyme Q oxidoreductase is also an electron-transporting molecule and is involved in the breakdown of fatty acids and amino acids. ANT (adenine nucleotide translocator) is also involved in oxidative phosphorylation as an energy carrying molecule. Each of these eight complexes plays a vital role in the health of the cell and any slight mutation in any one of the proteins that make up these complexes can lead to cell death or stress, which can both in turn lead to a number of diseases.

Variation Section[edit]

Variation[edit]

Somebody deleted the section that reads: 

"The rate of mutation in mtDNA is calculated to be about ten times greater than that of nuclear DNA, possibly due to a paucity of DNA repair mechanisms and/or the greater incidence of mutagenic free radicals in mitochondria. This high mutation rate leads to a high variation between mitochondria, not only among different species but even within the same species. It is calculated that if two humans are chosen randomly and their mtDNA is tested, they will have an average of between fifty and seventy different nucleotides. This may not seem like much, but when compared to the total number of nucleotides of a human mitochondrial DNA molecule (16,569), as much as 0.42% of the mtDNA varies between two people."
I agree that it should be sourced, but is it considered outright vandalism to be removed? Note that they are describing a per base comparison. --RebekahThorn (talk) 18:45, 8 January 2013 (UTC)[reply]

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How many types?[edit]

There are a few things I wanted to know but they're not in the article. Do we know how many different haplotypes exist? If you analyze the mtDNA of some random person, what are the chances that it will be exactly the same as a known mitochondrial genome? How much variation is there in the amino acids of the proteins coded in mtDNA? Apart from mitochondrial "diseases", how much variation is there in the function of mitochondria, due to mtDNA? Are some mtDNA haplotypes better than others, in terms of physical fitness potential for example? If someone can answer some of these questions, I would appreciate it. Eric Kvaalen (talk) 12:41, 10 July 2017 (UTC)[reply]

External links modified[edit]

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ETC protein table mistake?[edit]

Wanted to bring this to the attention of anyone with more editing experience/more experience with mt genetics. I believe the light vs. heavy chain assignments are flipped? This states that all the ETC proteins are encoded by the L chain except MT-ND6. I believe it's the opposite: MT-ND6 is the only protein encoded by the L chain while the rest are on the H chain. Doughpamine (talk) 19:54, 1 November 2021 (UTC)[reply]

edit: it actually seems that the entire table is incorrect with respect to L vs. H assignment.

Mutation rate[edit]

What is the mutation rate of human mtDNA? --95.24.68.60 (talk) 15:10, 25 March 2024 (UTC)[reply]

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