tag:blogger.com,1999:blog-7785493.post7523975421638639680..comments2024-01-04T04:11:55.717+02:00Comments on Dienekes’ Anthropology Blog: Or, maybe, modern humans and Neandertals didn't mix after all?Dienekeshttp://www.blogger.com/profile/02082684850093948970noreply@blogger.comBlogger17125tag:blogger.com,1999:blog-7785493.post-72999322640787035222012-08-16T07:29:39.658+03:002012-08-16T07:29:39.658+03:00"I can't be the only person here who foll..."I can't be the only person here who follows John Hawks'...he's building a case that Europeans DO have more individuals with 3+". <br /><br />I have just had my attention drawn to the post where he claims that Otzi has even more neanderthal genetic contribution than does an modern human group. terrythttps://www.blogger.com/profile/17327062321100035888noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-83217038113239023592012-08-15T13:19:51.887+03:002012-08-15T13:19:51.887+03:00I can't be the only person here who follows Jo...I can't be the only person here who follows John Hawks'...he's building a case that Europeans DO have more individuals with 3+. And the post has been out for quite a while.Justinhttps://www.blogger.com/profile/14658198296423491764noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-36770002799894120112012-08-15T06:12:09.258+03:002012-08-15T06:12:09.258+03:00Thanks for the updates.
"natural selection...Thanks for the updates. <br /><br />"natural selection on mtDNA; but it is difficult to see why Neandertal mtDNA would be selected against". <br /><br />And almost certainly wasn't selected against genetically. I think you supply the answer yourself: <br /><br />"the argument of Neandertal-to-modern introgression seems to be against experience, since it is the successful, expanding populations that usually affect the less successful, contracting ones, rather than the opposite" <br /><br />That would explain both the absence of Neanderthal haplotypes and the low level of admixture in modern humans. <br /><br />"But, we see that East Eurasians don't seem to lack in the Neandertal affiliation department". <br /><br />The explanation again seems to be contained within your comments: <br /><br />"This issue was addressed in a paper by Currat and Excoffier, who cleverly exploited the fact that the Neandertal range is now known to have stretched a good way towards the east to 'up' the opportunity that migrating humans would have encountered Neandertals as they made their way that way too. But, note, that this is not consistent with a coastal migration theory" <br /><br />I thought that the coastal migration theory is well and truly dead. I have long held the opinion that Y-DNA C and mt-DNA N moved east far to the north of the southern coastline. Descendants of both haplogroups are the main ones in Australia and could have carried both Neanderthal and Denisova genes east and south. Neanderthal presence far towards the east is consistent with this idea. <br /><br />"East Eurasians would have to follow a very specific northern path to Asia, to give them 'equal opportunity' to admix with Central Asian Neandertal groups". <br /><br />As you can see, I accept that elements of the East Asian population did so. <br /><br />"East Eurasians would have admixed with a different set of Neandertals that would have been different from European Neandertals like Vindija, and would still be expected to match Vindija less at least for that reason". <br /><br />Perhaps the difference was slight. Don't we already know that genetic variation within Neanderthals was very limited? <br /><br />"The third idea, is that what we are seeing as Neandertal admixture into modern humans may in fact have been modern human admixture into Neandertals". <br /><br />I agree it was most likely two way gene flow, with the major flow being from modern to Neanderthal. <br /><br />"Africa and Eurasia are represented as a linear string of identical populations (demes), each of which can exchange migrants only with its adjacent neighbors". <br /><br />Until one or other groups migrates some distance. But the assumption seems very obvious to me. After all it holds true for virtually every species. Most species form a cline of variation across their geographic range. Where the cline is broken we are able to divide the 'species' into subspecies'. And the human population at present can largely be 'represented as a linear string of identical populations'. In other words, the more things change the more they stay the same. <br /><br />"within the ancestral population of both modern humans and Neandertals (presumably Homo heidelbergensis), demes who were geographically close would be closer related". <br /><br />Same today. <br /><br />"I have a feeling that the conversation has only just begun". <br /><br />Convincing discoveries will be made. terrythttps://www.blogger.com/profile/17327062321100035888noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-5512111734564244322012-08-14T23:07:23.534+03:002012-08-14T23:07:23.534+03:00Not sure how extensively Australo-Melanesians have...<i>Not sure how extensively Australo-Melanesians have been sampled.</i><br /><br />I think modern Australoids have been sampled extensive enough (Australia, New Guinea, Melanesia and even some Negrito lands) for Denisovan alleles to make reasonable estimates about their amounts of Denisovan ancestry. Among modern Australoid groups, only western Negritos, whose Australoidness is doubtful, seem to lack Denisovan admixture.Onur Dincerhttps://www.blogger.com/profile/05041378853428912894noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-864175371359953172012-08-14T21:30:28.747+03:002012-08-14T21:30:28.747+03:00Not sure how extensively Australo-Melanesians have...Not sure how extensively Australo-Melanesians have been sampled.<br /><br />Also, it would make sense for archaic uniparental markers to be lost in that case because presumably not too many people would have reached that far as they expanded, there were lots of physical obstacles, so drift was probably a bigger issue.Dienekeshttps://www.blogger.com/profile/02082684850093948970noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-23921250800819329912012-08-14T21:27:25.602+03:002012-08-14T21:27:25.602+03:00So, while the evidence from uniparental markers do...<i>So, while the evidence from uniparental markers does not exclude Neandertal admixture, it seems to argue against it being substantial.</i><br /><br />Modern Australoids do not carry Denisovan haplogroups, but they seem to show more Denisovan admixture than the possible amount of Neanderthal admixture in modern Eurasians. How do you explain that? I am asking this because I have yet to see anyone who doubts the existence of relatively significant Denisovan admixture in modern Australoids.Onur Dincerhttps://www.blogger.com/profile/05041378853428912894noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-54866351816850587512012-08-14T20:54:26.787+03:002012-08-14T20:54:26.787+03:00Also, given the fossil and toolset evidence, there...<i>Also, given the fossil and toolset evidence, there is no reason to make such an Africa-centric assumption, in the first place. Why would population structure and admixture only exist and happen in Africa?</i><br /><br />Africa is very large, its size is often underestimated in Mercator map projections.<br /><br />It is also very climatically diverse, spanning many degrees of latitude.<br /><br />Plus, we do have evidence of structured populations in Africa today; West Eurasians or East Eurasians are like clones with respect to different African groups.<br /><br />And, we also see evidence of modern- and archaic-looking humans co-existing in Africa down to the terminal Pleistocene, the population does not appear uniform.<br /><br />So, there are many reasons to think that African population structure has played a big role.<br />Dienekeshttps://www.blogger.com/profile/02082684850093948970noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-81670778703979184082012-08-14T20:44:37.511+03:002012-08-14T20:44:37.511+03:00What I don't like about the Eriksson & Man...What I don't like about the Eriksson & Manica paper is that they take a very Africa-centric stance. Sure, with the data we have at this point, and simplistic statistics, they can show that population structure in Africa alone suffices. But that doesn't answer anything at all.<br /><br />Also, given the fossil and toolset evidence, there is no reason to make such an Africa-centric assumption, in the first place. Why would population structure and admixture only exist and happen in Africa?<br /><br />Finally, I don't trust admixture time estimates at the present, especially if additional population structure is involved. Admixture could have taken multiple steps both in NW Africa and West Asia.<br />eurologisthttps://www.blogger.com/profile/03440019181278830033noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-74716033046876537252012-08-14T19:27:05.615+03:002012-08-14T19:27:05.615+03:00Why the anomaly of Tuscans having higher “Neandert...Why the anomaly of Tuscans having higher “Neanderthal similarity” than Brits? RE: John Hawk's weblog 02-08-2012. Recall the mathematical models for human inter-relatedness proposed by Steve Olson, Joseph Chang, Douglas Rohde, Jotun Hein. Forty-thousand years seems like enough time for small inheritances to even-out across a continent. We may be looking at inferences that are not quite grounded.Sgt. Gilhttps://www.blogger.com/profile/16093774878169751410noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-53004917422645323392012-08-14T16:50:07.522+03:002012-08-14T16:50:07.522+03:00FYI - the Geno 2.0 project will be providing Neand...FYI - the Geno 2.0 project will be providing Neandertal admixture percentages, as now does 23 and Me. Mine was 3% and according to 23 and Me was at the 96th percentile, indicating they average a much lower percentage. Mark Dhttps://www.blogger.com/profile/03792117663748801194noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-81004577458716296752012-08-14T07:10:01.201+03:002012-08-14T07:10:01.201+03:00I've just read the abstract for the Mendez pap...I've just read the abstract for the Mendez paper and see that 'N' is a name for a particular mutation in STAT2. However my question regarding mt-DNA haplogroup N still stands.terrythttps://www.blogger.com/profile/17327062321100035888noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-53198180322241877592012-08-14T07:04:25.038+03:002012-08-14T07:04:25.038+03:00"I ended up adopting a position similar to wh..."I ended up adopting a position similar to what Mike Hammer seems to have described in a recent talk; both African structure and Neandertal introgression could account for the D-statistic pattern, and we didn't know exactly where we were along the continuum". <br /><br />To me that is the most likely explanation. Both. <br /><br />"If there was no admixture, than both the Neandertal and N haplotype would have had to have mutated in the same fashion after the human Neandertal split". <br /><br />Talking of N, what happened to the paper claiming to show N originated in the Persian Gulf oasis? It is supposed to be free view by now. terrythttps://www.blogger.com/profile/17327062321100035888noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-74456962605115612912012-08-14T03:21:49.946+03:002012-08-14T03:21:49.946+03:00In the Mendez et. al paper they say that the STAT2...In the Mendez et. al paper they say that the STAT2 locus has a MRCA of about ~80kya between neandertal and the N haplotype found in modern eurasians at low frequences. While the N-haplotype compared to human reference diverged 609kya. Note that they used the old 6M Chimp human divergence to calculate this so numbers should be adjusted up. Doesn't this strongly imply against structure in favor of admixture. If there was no admixture, than both the Neandertal and N haplotype would have had to have mutated in the same fashion after the human Neandertal split. This would be highly unlikely. So its unlikely to be just population structure. But as you say its a likely mixture of both if your Out-of-Arabia hypothesis is correct.jeffhsu3https://www.blogger.com/profile/09614165485710166361noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-72665890068961049332012-08-14T01:21:09.441+03:002012-08-14T01:21:09.441+03:00Btw, I wonder if the newly found archaic admixture...Btw, I wonder if the newly found archaic admixture in sub-Saharan Africans could mean that they also converged together with this new unknown species, or if it's simply actual admixture.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7785493.post-68521565463824021042012-08-14T01:19:12.169+03:002012-08-14T01:19:12.169+03:00And just some minutes ago I kept thinking European...And just some minutes ago I kept thinking Europeans had more Neanderthal admixture.<br /><br /><i>The findings of a study by researchers at the University of Cambridge suggests that common ancestry, not hybridisation, better explains the average 1-4 per cent DNA that those of European and Asian descent (Eurasians) share with Neanderthals.</i><br /><br /><i>Since Neandertals share genes that are exclusively characteristics of Eurasians but not Africans this actually suggest that Neanderthals and Eurasians have a common ancestor to the exclusion of sub-Saharan Africans.</i><br /><br />Which greatly supports the Out-of-Arabia theory, already backed up by Freidline et al. Proto-Eurasians and Neanderthals converging together in the Middle East before spreading outwards ≈70,000 years ago.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-7785493.post-18735083757221932812012-08-14T00:51:07.077+03:002012-08-14T00:51:07.077+03:00Excitig times indeed. My 2cnts:
Africans may hav...Excitig times indeed. My 2cnts: <br /><br />Africans may have some archaic introgression that Eurasians including Neandertals don't. That might correspond to A1/A2 Y-DNA hgs and L0/L1 mt-DNA hgs. <br /><br />If some of those are from archaic humans (archaics did survive longer in Africa), there is your "haplogroup from admixture" right before our eyes. Instead of searching in vain for it in Eurasia, why not investigate what is already evident in Africa?<br /><br />Anyhow, let's wait for more ancient DNA data.<br />aramthttps://www.blogger.com/profile/04486006044411081900noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-2771484680811604552012-08-13T23:53:17.640+03:002012-08-13T23:53:17.640+03:00Since Neandertals share genes that are exclusively...Since Neandertals share genes that are exclusively characteristics of Eurasians but not Africans this actually suggest that Neanderthals and Eurasians have a common ancestor to the exclusion of sub-Saharan Africans. <br /><br />Marcel F. WilliamsMarcel F. Williamshttps://www.blogger.com/profile/16245086958213100840noreply@blogger.com