Talk:Most recent common ancestor

Problem with "cats and dogs"

"for example, the MRCA of all Carnivora (i.e. the MRCA of "cats and dogs") is estimated to have lived of the order of 42 million years ago (Miacidae).[4]"

Carnivora are lions, tigers, bears, as well as canids. The MRCA of Canids is 60 million years ago. Canids include dogs, wolves, etc.

Problem wit Identical Ancestors Point

I have made some changes in that section and, been no native english speaker, I absolute agree with having been corrected. But before erasing my contribution you should read carefully it and the article of IAP: this is NO SCIENCE at all, but a fallcious huge mountain of biased lies. This part of the article is absolutely false and fallacious. It tends to probe a thing in scientific-like lenguage with no scientific thought in it at all. People is not getting it SIMPLY BECAUSE ITS FALSE. There's no proof of such a thing as IAP to have happened in the past, for sure not MANDATORY and statistically VERY uneven. And if, by some very weird chance, this thing happened in the past it only could be in the population bottleneck of 75.000 years ago, BUT THERES NO GENETIC OR OTHER proof for that; or going back and back in life history up to the very beginning of pluri-cellular life.

What I clearly see is the long hand of religious crap underneath it all: the date of 5.000 years is such a joke in terms of MRCA and historical proofs of isolated populations that can only came from the crapy young earth creationists. I don't want and really don't think it worths my time fighting with fanatics or well paid guys (hi, Heritage guys!) to begin an editions war but I beg for someone with wiki authority to have an eye on this before we begin to hear this crap as a 'scientific proof for Adam and Eve and original Sin supported by wikipedia' in the media.

For the supporters of that crap: I wish all your ignorance presents its bill to you soon.

I just want you editors to read things critically and using your reason and mind. Please, please have an eye on this. — Preceding unsigned comment added by Cohelet (talk • contribs) 20:49, 19 March 2013 (UTC)

Don't post this crap here. The talk page is for dicussing ways to improve the article. Nobody cares about your opinion. Your opinion doesn't matter here. Where is your proof that it's all a lie? Why have you not provided reliable sources to back up your claim? Why are you under the impression that this article implies there is scientific proof for IAP? It does not. Dkspartan1 (talk) 06:00, 20 April 2013 (UTC)

Cohelet -- regardless of what the effects of the Toba volcano may have been, it seems quite likely that multiple episodes of human evolutionary change took place within relatively small populations (since it's easier for a mutation to establish itself in a small population than in a large population etc.). The transition from 48 chromosomes to 46 likely took place within a relatively small population. A species having a relatively small population for number of generations means that the identical ancestor point is not too far back. Also, if the living members of a "species" don't have identical ancestors until several branchings up on the tree of species differentiation, then it's not likely to be a valid species at all... AnonMoos (talk) 08:03, 20 April 2013 (UTC)

I posted this to WT:GENETICS in response to the concerns of another editor which came up at WP:EAR: I actually just read the Rohde et al. article. It actually doesn't say anything about "5 to 10 thousand years ago". I tried to wrap my head around their statements to see if I could independently arrive at the article's 5 to 10k years ago claim via routine calculations, but could not. There are several statements about mean identical ancestor points arrived at in their simulations depending on changes to variables and the models, placing it at 2,158 BC, or 5,353 BC, and also noting that if people in Tasmania were totally reproductively isolated until 1803, then the latest possible identical ancestor point corresponds to the flooding of the Bass Strait some 9,000–12,000 years ago. Honestly, I think this is far enough away from routine calculations to make the claim in most recent common ancestor constitute original research. At the very least it probably needs in-text attribution to the authors. —/Mendaliv/^2¢/_Δ's/ 20:02, 20 May 2013 (UTC)

So, what, should this be removed? Corrected? I don't know enough about this subject to properly address it but I know it doesn't click. TangoFett (talk) 14:17, 6 April 2015 (UTC)

Yes, I have removed it. The paper was about a trivial model, making very simplistic assumptions about migration. The paper has scientific merit in showing how migration affects the IA, but the numbers coming from the model are clearly nonsense. 13:33, 27 July 2015 (UTC) — Preceding unsigned comment added by LachlanA (talk • contribs)

I am not sure you appreciate they calculate the MRCA for 2004, and not for 1803. Clearly, the MRCA before 1800 would have been very ancient indeed. But after contact, it doesnt take more than a few generations to spread admixture throughout the recently-contacted population, radically reducing the age of the MRCA. I am sorry if I am misreading the above and you are in fact aware of this. --dab (𒁳) 13:00, 21 October 2016 (UTC)

unwatched? semiprotect?

I am kind of losing hope for this page. I visit it every couple of years and clean up the worst attrition, but somehow, utter misconceptions always pop back almost immediately and remain unchallenged (in this case, since 2012). I'll try to clean up the page once again, but if you are watching it, please be wary of people adding "explanations" without citing additional sources. --dab (𒁳) 13:06, 21 October 2016 (UTC)

Exact meaning of "most recent" in genealogy

The first sentence of the article says: In biology and genealogy, the most recent common ancestor [...] of any set of organisms is the most recent individual from which all organisms in a group are directly descended.

Focussing on genealogy here, and taking two (distant) cousins as any set of organisms, the meaning of the term most recent individual is possibly confusing. In (genetic) genealogy, MRCA often refers to 'most recent in terms of fewest generations back', and is used in the context of comparing DNA test results. For example, in the case of two second cousins who share a great-grandparent born in 1850, and who (via a different path) also share a greatgreat-grandparent born in 1860, the great-grandparent would be the MRCA for genetic genealogy purposes, but the greatgreat-grandparent would be the MRCA in the more common meaning discussed in this article. Generation gaps can be quite different in different ancestry lines, so this situation does happen in family trees, especially if you go back more generations than 3 or 4.

Since genealogy is mentioned in the lead sentence, I think it would be good if the article would clarify the exact meaning of "most recent". Does anyone have more knowledge about this? I can't find good sources that clearly define MRCA in genealogy context. Gap9551 (talk) 18:42, 12 October 2017 (UTC)

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Two more sources

[1] and [2]. Doug Weller talk 18:05, 17 July 2018 (UTC)

Human MRCA

I have deleted the statement that the human MRCA may be as recent as 3000 years ago as it is not supported by the sources. The first is about a computer model and the second, 'JC Virus Evolution and Its Association with Human Populations', says "this virus should not be used as a marker for human population history". Dudley Miles (talk) 18:02, 19 August 2018 (UTC)

@Dudley Miles - this is a theory with high likelihood, not a categorical truth. The word "may" is the key. A lot of prehistoric knowledge is essentially result of models. I would not write off so easily a mathematical model or a model based on a virus so closely associated with humans, specially when more than one model give similar results.

My own genealogical research showed me that a closed community of one thousand individuals today, are all related to everyone who lived there 6 generations ago. Assuming 20-25 years per generation this means 100-150 years. The mathematical model expresses this more generally with a formula and deduces the time range for the whole world population. What is wrong with that? An indication of the approximate range for truth is better than complete ignorance. Publishing a range is a call for improvement which is better than censorship. Cobanyastigi (talk) 02:33, 20 August 2018 (UTC)

@Cobanvastigi:, following our policies and guidelines is not censorship. We rely on sources that meet our criteria for reliability and back the text we are using them for. Neither of these sources seem to do that. Our own opinions, experience or research are irrelevant. By the way, @ by itself does nothing, if you wish to notify someone you need to do something such as {{re|Cobanvastigi}} - and you have to get it right the first time, you can't fix it. If you get it wrong you need a new and signed post. Doug Weller talk 13:16, 20 August 2018 (UTC) Ironic, I couldn't see that your name was spelled with a y because my software was underlining it for spelling. @Cobanyastigi: - my bad for not using preview. Doug Weller talk 13:18, 20 August 2018 (UTC)