Talk:Mitochondrial Eve

From Wikipedia, the free encyclopedia

WikiProject Genetics This article is part of WikiProject Genetics, an attempt to build a comprehensive and detailed guide to genetics on Wikipedia. If you would like to participate, you can edit this page, or visit the project page to join the project and/or contribute to the discussion.
??? This article has not yet received a rating on the quality scale.
??? This article has not yet received an importance rating.
Former featured article Mitochondrial Eve is a former featured article. Please see the links under Article milestones below for its original nomination page (for older articles, check the nomination archive) and why it was removed.
Good article Mitochondrial Eve has been listed as one of the Natural sciences good articles under the good article criteria. If you can improve it further, please do. If it no longer meets these criteria, you can delist it, or ask for a reassessment.
Main Page trophy This article appeared on Wikipedia's Main Page as Today's featured article on July 28, 2004.
WikiProject Spoken Wikipedia The spoken word version of this article is part of WikiProject Spoken Wikipedia, an attempt to produce recordings of Wikipedia articles. To participate, visit the project page.
This article is within the scope of WikiProject Human Genetic History, a collaborative effort to improve Wikipedia's coverage of genetic genealogy, genetics-based population history, and associated theory and methods. If you would like to participate, please visit the project page, where you can join the project and/or contribute to the discussion.
Molecular and Cellular Biology WikiProject
MCB Portal
This article is within the scope of the Molecular and Cellular Biology WikiProject. To participate, visit the WikiProject for more information. The WikiProject's current monthly collaboration is focused on improving Restriction enzyme.
Good article GA This article has been rated as GA-Class on the assessment scale.
Top This article is on a subject of Top-importance within molecular and cellular biology.

Article Grading: The article has been rated for quality and/or importance but has no comments yet. If appropriate, please review the article and then leave comments here to identify the strengths and weaknesses of the article and what work it will need.
Archive
Archives
Archive 1


Contents

[edit] MRCA versus IAP

The article states: No contemporary of Mitochondrial Eve or Y-chromosomal Adam is an ancestor of only a subset of people alive today, because both of them lived much longer ago than the identical ancestors point.

However, this is not possible, as the IAP is necessariy further in the past than the MRCA - as correctly stated in the article on identical ancestors point: In genetic genealogy, the identical ancestors point (IAP) is that point in a given population's past where each individual then alive turned out to be either the ancestor of every individual alive now, or to have no living descendants at all. This point lies further in the past than the population's most recent common ancestor (MRCA).

I have deleted the paragraph, because it is wrong, and I cannot immediately see how to make sense of it. —Preceding unsigned comment added by 87.72.95.45 (talk) 22:51, 21 April 2008 (UTC)

[edit] MRCA lived 3000 BP?

The article states that the MRCA of all humans (not M. Eve or Y. Adam) lived 3000 BP. But the land bridge to the Americas was crossed over 15,000 BP and there was no significant contact between the old and new worlds from atleast a couple thousand years after that until 1492 (vikings contact with northern tribes don't count I don't think). There are Amerindians that have no European descent right? So how can they have a MRCA in common with Europeans AFTER the land bridge was crossed but before 1492? I can't fathom how that is possible? Brentt 23:38, 13 April 2007 (UTC)

I know. I found it hard to believe myself at first. But see the Time Estimate section in Most recent common ancestor. Dawkins also talked about this in the Ancestor's Tale. Fred Hsu 03:05, 14 April 2007 (UTC)

Actually the Viking influence would be very relevant to the Amerindian / MRCA date question. It would only take one cross-breed left behind.... --Michael C. Price talk 08:30, 14 April 2007 (UTC)

This makes no sense, how can every human on earth have the same matrilineal ancestor stretching back only 3,000 years, this has to be an error. —Preceding unsigned comment added by 24.125.69.227 (talk) 09:40, 28 May 2008 (UTC)

[edit] Nominated most ancient common ancestor for deletion

Someone created a new article called Most ancient common ancestor. Notice that it is ancient, not recent. It appears to be a new name coined by the author without research backing (i.e. original research). I nominated that page for deletion. Please visit Wikipedia:Articles for deletion/Most ancient common ancestor if you wish to participate in the discussion. I am posting this message in this discussion page because the topic in question is closely related to this article. Again, please note that I am not nominating the Most Recent Common Ancestor article for deletion; I am nominating the newly created Most Ancient Common Ancestor. Fred Hsu 05:42, 21 July 2007 (UTC)

[edit] Confused paragraph

A paragraph has been added to the misconceptions section:

Suppose Mitochondrial Eve lived before the identical ancestor point. Then, she would have to live with some people that are not ancestors of all the population and who have passed-on their own mitochondrial dna to their descent up to now. As such Mitochondrial Eve can not be considered the Most Recent Common Ancestor for Mitochondrial DNA because a subset of the common descent will not bear its mitochondrial DNA. Note that this reasoning can be applied to all genes, which means that a gene-specific MRCA has to be older than the identical ancestor point.

It seems rather confused to me.--Michael C. Price talk 15:07, 4 August 2007 (UTC)

I removed it. 'Ancestors' referred to in identical ancestors point are ancestors via both paternal and maternal lines. An ancestor in this case may actual leave no gene from himself/herself today because of meiosis and recombination. mtEve is defined strictly by mitochondria inheritance, on the other hand. I can't fathom how one can produce an argument based on identical ancestor point and mtEve based on this logic. But I could be wrong. But until a better paragraph is written and reference is cited, I don't think we should have the above in the article. Fred Hsu 15:38, 4 August 2007 (UTC)
I just moved the sub-section on identical ancestors point in Most_recent_common_ancestor#MRCA_of_all_living_humans to a different place. Hopefully this will make it more clear. Fred Hsu 15:55, 4 August 2007 (UTC)
Further clarified this in Identical ancestors point. Fred Hsu 16:03, 4 August 2007 (UTC)
I though an "absurd reasonning" could clarify the timeline between Mitochondrial Eve and Identical Ancestor Point. I will double check what I wrote and try to have a clearer version. --Donvinzk 20:00, 4 August 2007 (UTC)
I suggest you talk through changes here first, before altering the article.--Michael C. Price talk 21:32, 4 August 2007 (UTC)
I will for sure since all previous edits have been immediately reverted. As for the last one, it was just to give a small explanation to the assertion "contemporary woman to mitochondrial eve can not have matrilineal descent to current population", which I did not grasp at first and though I could help others similar to me. I wanted to use "contraposée" and "absurd reasoning" which are French barbarism since I can not find the English term.--Donvinzk 00:21, 5 August 2007 (UTC)
Proof by contradiction is the term.--Donvinzk 00:21, 5 August 2007 (UTC)
Okay, I see where you are coming from. I'll try to clarify the section. --Michael C. Price talk 00:25, 5 August 2007 (UTC)
Obviously, you meant to improve the article. We appreciate that. The article already states "every mtDNA in every living person is derived from hers..." in the lead section. If every mtDNA in every person is from mtMRCA, then obviously no other contemporary woman of mtMRCA could have passed down her mtDNA. As MichaelCPrice said, your absurd reasoning isn't helping in this case. We can add the same absurd reasoning to pretty much every single wikipedia article. Notice how the paragraph rigth above the on you last edited talks explicitly about how contemporary women of mtMRCA could have left descendants today, but her descendants will NOT have her mtDNA. Fred Hsu 00:28, 5 August 2007 (UTC)
I think it's mostly a language issue -- I won't add anything unless it looks quite necessary. But it has to be admitted that some parts of the article do require close reading; but then it is a complex subject to outsiders. --Michael C. Price talk 00:38, 5 August 2007 (UTC)
No offense for me. I might understand things better argumenting by contradiction than by direct proof, and this does not mean I should edit every single articles to fulfill this need. However, it is a complex subject, I am an outsider to the field, and I think the article might need some "graphic" example, I'll share ideas here if I think of something. (And, by the way, my argument was a tautology, not a non sequitur ;-) )
Correction accepted.  :-) --Michael C. Price talk 01:02, 5 August 2007 (UTC)

Michael, thank you for copyediting. I think, however, you may want to preserve this line: "Eventually, only one single lineage remains which includes all mothers alive today and their male and female children.". That paragraph talks about how females pass mtDNA to daugheters. Sons are dead ends as far as mtDNA is concerned. This sentence is explicitly saying that the 'last' generation of mothers pass the same mtDNA down to living people at the present. Fred Hsu 01:24, 5 August 2007 (UTC)

The previous wording seemed to leave open the possibility that we know of humans-alive-today-with-deceased-mothers with different mtDNA. Now I know that it is extremely unlikely (but not impossible) -- but the wording seemed to suggest it was a known fact. So it should be written "Eventually, only one single lineage remains which includes all mothers alive today and their male and female children and all mothers not alive today and their male and female children who are alive today." -- so we might as well just say "everybody alive today". --Michael C. Price talk 01:43, 5 August 2007 (UTC)

[edit] mt DNA statement

The statement

Unlike mtDNA, which is outside the nucleus, genes in nuclear DNA become mixed because of genetic recombination, and therefore we can be statistically less certain about their origins.

seems wrong. Whilst mtDNA is outside the nucleus this has nothing to do with recombination (a single mitochondrian contains multiple copies of mtDNA and undergoes recombination to maintain its integrity). Thus it is not the recombination that is the source of the mixing but the fact that we inherit two nuclear alleles, one from each parent, whereas we inherit mtDNA from only one parent.--Michael C. Price talk 01:02, 5 August 2007 (UTC)

Yes, that paragraph can be made clearer: the trouble with tracking nuclear DNA is caused by both meiosis and Chromosomal crossover/Genetic recombination. See better phrasing at Most_recent_common_ancestor#Patrilineal_and_matrilineal_ancestry. Fred Hsu 01:32, 5 August 2007 (UTC)

Michael, I see that you have also enhanced Mitochondrion. As I said in previous comment, the difficulties with tracking nuclear DNA is not only due to the 1/2 chance of inheritance from either parent. Yes, that makes it more difficult, but you can still infer statistically about what would happen in a long period of time. But with further recombination, the task becomes exponentially more difficult. I have read it somewhere, and perhaps I'll find references to it. I don't think it is wise to simply drop recombination from the article. Fred Hsu 04:57, 5 August 2007 (UTC)
But the tracking difficulty with nDNA can't be due to recombination per se, since mtDNA also recombines. I've updated the description about recombination at Mitochondrial DNA and mentioned it here. --Michael C. Price talk 10:07, 5 August 2007 (UTC)

[edit] Wanted edit

In Science, 2. January 1998, the article "Calibrating the Mitochondrial Clock" refers to evidence that the 140 000 years referred to in this article are not so certain. Could someone please make this article a bit more balanced on this point? —Preceding unsigned comment added by Gubbanoa (talk • contribs) 21:07, 4 November 2007 (UTC)

Feel free to add the point yourself, but make sure you cite your source. WLU 21:08, 7 November 2007 (UTC)
You are right about me not putting the reference in the text and two wrongs do not make a right. However, I think it is a shame you took out critisism of the weak claim you have left unquoted. I cannot see why. —Preceding unsigned comment added by 195.204.181.130 (talk) 10:19, 12 November 2007 (UTC)
If you are very motivated, you should edit it with proper citation. Or at least provide an URL to make it easier for people to help you. At the moment, Mitochondrial_Eve#Eve_and_the_Out-of-Africa_theory should provide some of the answers. Yes, mitochondrial DNA alone is not enough to support African origin of 'human race'. However, it is good enough for the African origin of 'mtEve', as long as you keep in mind that mtEve is nothing special (there are thousands of other ways to trace common ancestry by different gene pathways). I'll try to find the article you are talking about when I have more time. Fred Hsu 03:22, 13 November 2007 (UTC)

[edit] Mitochondria in sperm

Someone inserted these (in bold):

[quote]We know about Eve because of mitochondrial organelles that are passed only from mother to offspring. (Strictly speaking, the sperm do bring some mitochondria to the egg, but their contribution amounts to at most about 0.01% of the fertilized egg's total, so is normally ignored.) Each mitochondrion contains Mitochondrial DNA (mtDNA). [/quote]

This is actually not quite right. One of Sykes book actually talks about how sperm mitochondria are destroyed by the egg or later in the embryo. I don't have time to look it up right now. But in any case, the main article on Mitochondrial DNA already talks about this. The section in MtEve actually links to it as 'main article'. There is no need to interrupt the flow of this paragraph with such details, in my view. I reverted the change. Fred Hsu (talk) 23:39, 25 December 2007 (UTC)

Yes, it was Sykes', Seven Daughters of Eve, that refutes the notion that some mtDNA comes from the father. Says that more detailed studies failed to show any such paternal effect. --Michael C. Price talk 20:30, 29 April 2008 (UTC)

[edit] Reference on date of Mitochondrial Eve

TalkOrigins has an interesting short article on the date of Mitochondrial Eve, with references. - http://www.talkorigins.org/indexcc/CB/CB621_1.html "created 2004-2-26" --
"Revised studies of all of the mtDNA ... placed the age of the most recent common mitochondrial ancestor at 171,500 +/- 50,000 years ago."
-- Writtenonsand (talk) 22:32, 5 January 2008 (UTC)

[edit] Suggestion to clarify opening sentence.

I suggest adding the qualification "via the mitochondrial DNA pathway" to the opening sentence, so it reads:

Mitochondrial Eve (mt-mrca) is the name given by researchers to the woman who is defined as the matrilineal most recent common ancestor (MRCA), via the mitochondrial DNA pathway, for all currently living humans.

Para 3 contains this qualification, and expands on it. Omitting the qualification in the opening sentence is potentially confusing (at least it was for me, having come to this page after reading the page on MRCA). —Preceding unsigned comment added by 58.41.169.168 (talk) 07:58, 12 April 2008 (UTC)

The word "matrilineal" (a link to another article) essentially means the same thing. So either we keep it the way it is, or we drop "matrilineal" and replace it with the longer qualification sentence. I vote for the shorter version, but I understand how how reader may miss this one word. Fred Hsu (talk) 16:13, 13 April 2008 (UTC)

I agree with Fred. The problem with the clarification is that it is redundant -- the matrilineal ancestor is, by definition, the mt contributor. A reader may think that these must be distinct concepts since they are both mentioned, which will really confuse them. The sentence as it is (now) looks fine.
I suggest the deletion of for over a hundred thousand years from the 2nd sentence, because mtDNA has been passed down for well over a billion years, not just 100,000. --Michael C. Price talk 20:27, 29 April 2008 (UTC)

[edit] Note to user: MichaelCPrice

Howdy -- I'm the author of the "concrete example," and I wanted to see if you thought a diagram might be better than a narrative? I have a sort of love affair (scientifically speaking) w/mitochondria and the whole dynamic of mitochondrial DNA is so fascinating, especially w/r/t "Mitochondrial Eve," that I want badly to make the notion of matrilineal descendence of m. DNA crystal clear, even to the most unscientific-minded. Sadly, though, and as much as I also love Wikipedia, I think this is one of those instances where words muddy instead of enlighten. I'm thinking about making a simple flow-chart-type thingie (via graphics software) to illustrate both the matrilineal line of mitochondrial DNA *and* how it's possible that Eve could have had contemporaries whose m. DNA was not passed on as Eve's was, but whose regular DNA *was*. I think that point is probably the basis for most laymen's confusion, and I think that ,as a result, it's at that point where the whole premise might lose its impact.

So I'll make a little graphic in the next few days & post it and you (and everybody else watching this page) can take a look and tell me what you think, yes?

cheers, Sugarbat (talk) 17:27, 29 April 2008 (UTC)

I hope you didn't mind me removing the concrete example you gave, but I found myself getting lost in the details. Anyway, glad to see that you took it positively: diagrams are always a great idea -- a picture paints a thousand words and all that -- so go right ahead. The concept definitely creates a lot of misconceptions for the layman, and anything that clarifies this is good.--Michael C. Price talk 20:17, 29 April 2008 (UTC)