Talk:Identical ancestors point

message: Perhaps should note that as we move back from the IAP the number of individuals (within the species) gets smaller and smaller until eventually there is only one.  This would be the Last common ancestor (see Wikipedia).  Depending on whether Multiregional or Recent Replacement is correct, the date of the LCA of modern man is either 2 Million BCE or 40,000.   The LCA does however, exist, and leads to the IAP. Tom Schmal 00:41, 2 November 2007 (UTC)
replies: text: Your understanding of the LCA is incorrect.  LCA is basically the same as MRCA, except that nowadays MRCA is used more often than not to define most recent common ancestor among a species (that is, common ancestor of a set of people), while LCA is used to define most recent common ancestor of a set of species.  You can think of LCA as what Dawkins calls 'concestor'.  Notice that both LCA and MRCA only make sense when applied to a 'set' of organisms.  Pay attention to the words 'most recent' and 'common'. See Most_recent_common_ancestor#MRCA_of_different_species. Fred Hsu 02:24, 2 November 2007 (UTC)

text: What you are trying to describe is the original individual whose gene undergoes a mutation which eventually become universal in an entire population later.  This individual has contemporaries.  Think about it, how would a single individual mate? Fred Hsu 02:24, 2 November 2007 (UTC)
thread_title:  ancestors to IAP 

message: Cool. I guess this will make it clear to people that identical ancestors point is NOT the same as MRCA. Fred Hsu 14:16, 23 July 2007 (UTC)
thread_title: Page restored

message: I removed this:
It should be noted that the 'identical ancestors point' is dependent upon the single recent origin hypothesis. Should humans have evolved from multiple sources and then merged, the concept cannot be correct. It should be noted that some species today (i.e. birds) have merged (also called species integration; thus it is possible for humans, as well, to have come from multiple origins. See the multiregional hypothesis for the alternate view.
Please cite references for merging of bird species.  Also, I think such arguments should be added to most recent common ancestor.  Notice that Mitochondrial Eve article already discusses this topic.
I am nominating the species integration for deletion (see its talk page).  Thus I don't believe this paragraph is appropriate at this time in this articl. Fred Hsu 23:20, 4 August 2007 (UTC)
replies: text: Even if the 'word phrase' is eliminated, the concept of 'multiple origins' is the basis of the multi-regional hypothesis. Given that the 'identical ancestors point' is contingent upon ideas widely perceived to be 'true' but which remain UNPROVEN, I find room to insert a 'caveat' into the article. Indeed, it was questions about the 'wobbling' of planets that led to the discovery of Pluto. However, it turned out that the 'wobbling' was an errant calculation--but fixing this calculation helped validate the theory of relativity. Questioning loopholes in scientific theory is an integral part of ensuring that we have the 'right answers', rather than simply being 'in the ballpark.'Ryoung122 09:48, 7 August 2007 (UTC)
replies: text: If my understanding of multiregional hypothesis is correct, this theory does not claim that modern human was a result of merging of multiple non-breeding species.  Instead, the theory states that basically the various descendant groups of Homo erectus (including Neanderthal) are all one interbreeding species.  It states that all these groups (one species) evolved around the world into Homo sapiens sapiens via frequent breeding around borders of regions.  If so, the calculation for MCRA and identical ancestors point is still perfectly valid for the multiregional hypothesis, as all such hominids are one single happy breeding species.  Fred Hsu 16:22, 7 August 2007 (UTC)
replies: text: Dawkins provides a diagram for the multiregional theory in The Ancestor's Tale, based on Alan Templeton.  The multiregional theory postulates "Out of Africal again and again", three waves of African exodus, the earliest being Erectus about 1.7 million years ago.Skates61 (talk) 05:01, 16 February 2009 (UTC)
thread_title:  removed the caveat section 

message: The information held on Identical Ancestor Point appears to be questionable. .14:28, 17 August 2007 (UTC)
thread_title: Versus MRCA

message: 1. Some simple examples of what is being discussed (such as given in last common ancestor)
2. A diagram or two
3. Rewriting for style and clarity.
I would give this last a go now, but I'm a bit hazy on some of the details. If no one has done it in a couple of weeks, I will attempt it. Myles325a (talk) 04:02, 10 May 2008 (UTC)
thread_title:  What this article needs now 

message: This article describes a concept of a common ancestor living 5,000 to 15,000 years ago.   However, it's reasonably documented that one fork of humanity moved to the Americas at least 10,000 years ago, and to Australia closer to 50,000 years ago, and as long as pureblood native americans and australians exist, a common ancestor dated after those forkings is not possible.
Is this article the result of speculation or (bogus) original research?--Bradtem (talk) 21:26, 13 July 2009 (UTC)
replies: text: Identical ancestors point is derived from most recent common ancestor (MRCA) which is statistically derived. Most people reject MRCA at face value by incorrectly assuming that the MRCA passed all his/her genes to all people today. In fact, the MRCA may not have passed one single gene to anyone living today. See the Time Estimates section on MRCA to answers to your question. Fred Hsu (talk) 04:59, 17 July 2009 (UTC)

text: Of course, if there is a group of pureblood natives which has never mixed with people from other continents directly or indirectly via population diffusion, yes the time estimates for MRCA and identical ancestors point will need to be drastically modified. Fred Hsu (talk) 04:59, 17 July 2009 (UTC)

text: As I pointed out above, there are still uncontacted tribes all over the world, such as the Sentinelese, and therefore the assertion "there are no isolated populations today" seems to be simply wrong. While it is obviously impossible for practical reasons to conclusively prove (for the time being) that the Sentinelese have seen no admixture, the assumption is plausible: There is no evidence for genetic admixture from mainland groups in other Andamanese groups, either (which does not preclude cultural contact, to address an objection on Talk:Andamanese people, but that is immaterial here), and there is no reason to think that the Sentinelese of all Andamanese groups form the big exception. The Andamanese have been isolated for millennia, possibly tens of millennia, as the genetic evidence strongly suggests. --Florian Blaschke (talk) 13:48, 29 October 2013 (UTC)
thread_title:  Dates suggested make no sense 

message: The article speaks about hominin and other animals. The hominin part ist problematic. 
That a IPA - found by a simulation or a pure mathematical model - can be realty has one precondition: all animals must mate together. Obviously: when populations are seperated over X a. they can't have the same ansestor <X a. Since some populations - for ex. the Onge of the Andaman Islands - are isolated for prox. 40 - 50 ma. the simutation model will not help, to find the time of the real MRCA or IAP. --Sophia Nabokov (talk) 09:49, 14 January 2011 (UTC)
thread_title:  hominin vs. other animals 

message: Must not this point be some time before the ancestors of non-Africans left Africa? --Oddeivind (talk) 21:18, 21 July 2012 (UTC)
thread_title:  Before leaving Africa?  

message: If we look at the nature article, it says "Besides dating our most recent common ancestor, Rohde's team also calculates that in 5,400 BC everyone alive was either an ancestor of all of humanity, or of nobody alive today. The researchers call this the 'identical ancestors' point: the time before which all the family trees of people today are composed of exactly the same individuals."
If we focus on the first sentence and take this as the definition of the "identical ancestor's point", then surely the definition of it being a specific momentary time in the past is meaningless? Is it not possible that we could go forward in time to say 5000 BC and that everyone alive then were either an ancestor of all of humanity, or of nobody alive today? Both sets of people would have had children and though some lineages may have died out in 400 years, you would still have descendants of both lineages. Of course, we could keep going forward in time till we reach a point in time when the last lineage, of one of the people alive at the IPA time but who did not have children with anyone who was in the lineage that was ancestral to all of humanity alive today, dies. Just before that point everyone alive was either an ancestor of all of humanity, or an ancestor of nobody alive today- i.e this last lineage person who's just about to die without reproducing. Just after that death, everyone alive is only ancestral to all of humanity. Surely then the definition in the first sentence above defines a range, whatever name you wish to call that range?
But hang on- surely you can go back in time beyond the "IPA" and it can still be the case whereby you have a situation where everyone alive was either an ancestor of all of humanity, or of nobody alive today- both groups of people can't just pop out of nowhere (of course that is till we go back to the LCA, but that's irrelevant in this discussion), they both had to have had parents. Unless they are talking about the most recent common ancestor of both of these groups of people- but then surely, that would be exactly the same person as the MRCA of all of humanity alive today? ...Unless, they are talking about a point in time where they population is split equally into two groups, 50% of everyone alive being an ancestor of all of humanity, and 50% of everyone alive being an ancestor of nobody alive today. But then surely, this could happen more than once in humanity's history, surely, it could even stay like that for a period? It's not as if the lineage that sired all of humanity alive today grew at a constant rate and that the lineage that did not shrank at a constant rate, is it? There can be bottlenecks in population for both groups of people, or a "bottleneck" can stay at the same width for some time.
And onto the second sentence in the quote above: "the time before which all the family trees of people today are composed of exactly the same individuals" or in the actual paper's words "The point beyond which everyone alive today shares the same set of ancestors". I honestly don't see how this isn't just the MRCA; consequentially I don't see how it could be further back in time than that TMRCA
Either definition, the one in the first sentence and the one in the second, is meaningless, or I'm missing something. What on earth are they trying to convey?  — Preceding unsigned comment added by 77.96.64.133 (talk) 20:28, 8 March 2014 (UTC)
replies: text: These points are defined with respect to the population alive at a given time, and can change when the population changes (through births and deaths).  Otherwise, I'm not too sure what you're asking.  It means that people have the same set of remote ancestors, not necessarily that they have the same individuals in exactly the same genealogical position ins their lineages... AnonMoos (talk) 01:38, 21 March 2014 (UTC)
thread_title:  Definition meaningless? 

message: The concept is sound, and I don't doubt that it appears in Dawkins 1995, but I suspect the name doesn't. And the Rohde (2003) paper (from which the doubted estimate above) is quoted in the article:
* The point beyond which everyone alive today shares the same set of ancestors is somewhat harder to predict, but... 
Which doesn't use the name "identical ancestors point". Now, I can't think what else "identical ancestors point" could possibly mean, so I'm not going to place whine-tags all over the article, but it would still be nice to have some source for the name. --God made the integers (talk) 21:20, 10 January 2017 (UTC)
replies: text: Did you see the external link http://www.nature.com/news/2004/040929/full/news040927-10.html ? -- AnonMoos (talk) 10:50, 11 January 2017 (UTC)
replies: text: No I hadn't, thanks. --God made the integers (talk) 20:30, 11 January 2017 (UTC)
thread_title:  Naming 

message: Estimates that put the IAP for modern humans very recent (like a few thousand years ago) confuses me. For example, if there are any Native Americans alive with ancestors who lived in America 5000 years ago, which I think it is safe to assume that it does, then if these estimates are correct then everybody on earth would have to have an ancestor that lived in America 5000 years ago. Every European and every African (notice the difference between this and MRCA). Surely this can hardly be the case. I find estimates at 15 000 years to be easier to swallow, but that brings me to another question. I have red that all humans from outside of Africa have some Neanderthal ancestry, but not sub-saharan Africans. I don't know if that is true (genetic similarities could be explained by common ancestors rather than direct descent), but since the Neanderthals disappeared well before 15 000 BC either everyone on earth has neanderthal ancestry or nobody does, if the IAP estimate is correct. Does anybody know anything about this?  — Preceding unsigned comment added by 84.55.118.131 (talk) 15:17, 17 November 2017 (UTC)
thread_title: Dating of IAP and neanderthals

message: Everyone is related earlier, at the time of the MRCA, as they are all at least distant half cousins through the MRCA.
I plan to update this article shortly to correct this and get the definition back to what Chang, Rohde and Olson explained. The article is also currently suffering from a lack of sourcing, in particular we are beginning to see genetic studies backing up the earlier simulations work, I will cite one. 
To all of you here who keep arguing for isolated populations, try to find one who has never mixed with their neighbors - it’s impossible. Even a tiny amount of mixing will introduce all the ancestry of the “mixee”, so to say, to the isolates.
Skates61 (talk) 22:06, 26 April 2018 (UTC)
thread_title:  Point 2 “Essentially, this would make the IAP the point in the group's past where everyone is related” is incorrect  

message: Should we include a reference to Adam Rutherford's categorical statement that this point is only 3400 years ago.  It's in his newly published book as reviewed https://www.theguardian.com/books/2020/jan/30/how-to-argue-with-a-racist-adam-rutherford-review but in the book he provides little in the way of back up. Nine-and-fifty swans (talk) 09:38, 8 February 2020 (UTC)
thread_title: 3,400 Years BP