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Author Topic:   New Type of Ancient Human Found—Descendants Live Today?
Jon
Inactive Member


Message 164 of 209 (600271)
01-13-2011 5:25 PM
Reply to: Message 161 by Taq
01-13-2011 2:31 PM


Re: Continuity of the Species
There was not the same gene flow between the populations as there was within each population.
This claim is based on ... ?
The major mechanism was migration, not gene flow.
Again, this is the claim to be supported. You cannot continue stating it as fact without any supporting evidence.
Divergence between the human groups evidences interrupted gene flow through mate selection
Interrupted, but not permanently ceased.
... the 95% dominance of African DNA in modern populations.
What of this DNA tells you it is African? And, why is genetic distribution a measurement of population movements?
We see zero Y-chromosome haplotypes from Neanderthals and the Denisova species moving from outside of African into Africa. All of the movement is out of Africa.
How are these measurements taken? Are only modern populations used? All the same, though, these distributions are neither a problem for MH nor evidence for OOA. Indeed, most of the genetic evidence involved in the debate is entirely ambiguous.
Jon

Check out No webpage found at provided URL: Apollo's Temple!
Ignorance is temporary; you should be able to overcome it. - nwr

This message is a reply to:
 Message 161 by Taq, posted 01-13-2011 2:31 PM Taq has replied

Replies to this message:
 Message 165 by Taq, posted 01-13-2011 5:52 PM Jon has replied

  
Jon
Inactive Member


Message 168 of 209 (600323)
01-13-2011 11:37 PM
Reply to: Message 165 by Taq
01-13-2011 5:52 PM


Re: Continuity of the Species
The genetic divergence of anatomically modern humans, neanderthals, and the Denisova species. This genetic divergence required 300,000 years of very limited to no gene flow.
Unfortunately the genetic evidence available cannot address this question, as the genetic difference between any modern and archaic population in the process of evolving will certainly be great.
Which I supplied with the Y-chromosome haplomap, the dominance of African DNA across the globe, and modern examples of the mechanism in action.
Interesting how the link between genetic flow and migration continues to be repeated ad nauseam without a single effort to support this extraordinary assumption.
The most diverse genetic groups are found in Africa, and they include the alleles found in human groups outside of Africa. Regional alleles are modifications of these African alleles (except for the tiny percentage of alleles from non-African, non-modern human populations). This means the source was Africa.
Never been disputed. Again, the issue for discussion is the validity of the assumed link between gene flow and migration.
These measurements are taken using molecular clock data using modern DNA. Since we are talking about the evolution of modern humans this seems to be a viable sample pool.
This is the first error: to believe we can discover truths about the past without ever needing look at it. Genetic samples are valuable, but they only make sense in light of a workable modelwe cannot use the present as a sole basis for a model of the past. Such fallacy is demonstrated by, for example, Alan Templeton, who's shown various analyses of the same genetic data to yield drastically different results. On top of this, higher selection pressures on the peripheries (where population numbers are low and thin) makes the termination of mtDNA lineages more prevalent in these regions, a possibility demonstrated as fact in Mungo Man. The factual possibility of these lost lineages shatters the presumed link between modern genetic diversity and population age.
I could go on, but...
Jon
Edited by Jon, : schpelling

Check out No webpage found at provided URL: Apollo's Temple!
Ignorance is temporary; you should be able to overcome it. - nwr

This message is a reply to:
 Message 165 by Taq, posted 01-13-2011 5:52 PM Taq has replied

Replies to this message:
 Message 170 by Taq, posted 01-14-2011 11:39 AM Jon has replied

  
Jon
Inactive Member


Message 171 of 209 (600422)
01-14-2011 12:25 PM
Reply to: Message 169 by Blue Jay
01-14-2011 10:08 AM


Re: Continuity of the Species
You seem to be going down the path that MR is just the hypothesis that modern humans interbred with other groups of Homo. This is not accurate. The reason MR comes into conflict with OoA is because both are hypotheses that attempt to explain the ancestry of modern, living humans, not just claims about whether some particular event (migration or hybridization) happened in prehistory.
I'm well aware of the differences between the two models. Neither is concerned solely with 'ancestry', especially given the varied nuances of that term. Where they conflict is primarily in their models of population movements.
So, the amount of evidence that remains to the present day is precisely the thing that the hypothesis is meant to be explaining, and is thus a direct measure of the correctness and explanatory power of the two hypotheses.
I see that neither model is crippled in explaining the present evidence. It is precisely the fact that both models are capable of explaining the present evidence that tells us the answer does not lie with present analysis alone: we must look elsewhere, and the only place else to look is to the past.
Because there is evidence demonstrating that both happened, and that people today are descended from both migrants and hybrids, we allow the predominant mechanism to dominate our paradigm. Thus, OoA remains the champion, with a minor contribution from MR.
Again, this is the claim you are supposed to be supporting. So far, I've seen no evidence offered that can corroborate this definitively. Repeated assertions of genetic histories will not do.
Jon

Check out No webpage found at provided URL: Apollo's Temple!
Ignorance is temporary; you should be able to overcome it. - nwr

This message is a reply to:
 Message 169 by Blue Jay, posted 01-14-2011 10:08 AM Blue Jay has replied

Replies to this message:
 Message 177 by Blue Jay, posted 01-14-2011 11:04 PM Jon has replied

  
Jon
Inactive Member


Message 172 of 209 (600434)
01-14-2011 1:07 PM
Reply to: Message 170 by Taq
01-14-2011 11:39 AM


Re: Continuity of the Species
Not if there is uninterrupted gene flow between the populations as the MR model proposes.
But, of course, the MH model doesn't propose uninterupted gene flow between populations.
What link? The genetic data points to very limited gene flow between the populations, not free genetic flow as the MR model proposes.
Again, that is not what the genetic data show; they show that there is a small amount of surviving genetic continuity. They do not and cannot provide insight into the amount of initial regional contribution, aside from showing that it occurred.
Our genomes are direct records of the past.
Absolutely false. I've demonstrated already that this is not the case.
The workable model is OoA. MR fails to be a workable model, as we have been discussing.
The claim that has yet to be supported, despite repetition of it as though it were fact ad nauseam.
Could you cite his work so we could all take a look? (apologies if you have already presented it in a previous post)
Sure, let me give you some references (I haven't yet read a couple of these, but am working on them; the first is the most relevant):
     Templeton, A. (1993). "The 'Eve' Hypothesis: A Genetic Critique and Reanalysis". American Anthropologist Vol. 95, 1. pp. 51—72.
     Templeton, A. (1994). "'Eve': Hypothesis Compatibility versus Hypothesis Testing". American Anthropologist Vol. 96, 1. pp.141—147.
     Templeton, A. (1998). "Human Races: A Genetic and Evolutionary Perspective". American Anthropologist Vol. 100, 3. pp. 632—650.
Those are just the ones I've got from Mr. Templeton. There are others, but he's quite prolific.
So why is it that African lineages dominate for both mtDNA and Y-chromosome DNA? Why do the Y-chromosome haplotypes create a pattern of migration?
If you're able to access those articles, give them a read. In short, the genetic evidence is not only ambiguous, but even if correct in the interpretation preferred for OOA, not evidence of population histories at all, but simply mtDNA histories:
quote:
Wolpoff & Caspari in Race and Human Evolution:
These genetic studies must be considered along with mtDNA and Y chromosome analyses indicating low levels of variation that might reflect a recent bottleneck. If these interpretations are correct, it means some genetic systems went through bottlenecks while others didn't. This would be an impossible finding if all human populations had gone through a recent bottleneck, but in fact all genetic systems do not have the same history, and therefore the history of the individual genetic systems is not population historyremember, if there was a common recent origin for all populations because a new species appeared, all of the genetic systems should reflect this and there could be none that did not pass through a bottleneck. But in fact this is what the genetic data, in aggregate, show did not happen. Some gene systems, for instance, mtDNA and certain segments of the Y chromosome, have gone through bottlenecks, but others have not. What this evidence means is that mitochondrial DNA evolution, indeed the evolution of other genetic systems, is not the same as population evolution. The "Eve" of mtDNA is just that, the last common ancestor of mtDNA lines, and not the last common ancestor of the humans who carry them. (1997, p. 308)
Let me know if you can't get those articles.
Jon
__________
Wolpoff, M. & R. Caspari. (1997) Race and Human Evolution. New York: Simon & Schuster.

Check out No webpage found at provided URL: Apollo's Temple!
Ignorance is temporary; you should be able to overcome it. - nwr

This message is a reply to:
 Message 170 by Taq, posted 01-14-2011 11:39 AM Taq has replied

Replies to this message:
 Message 173 by Taq, posted 01-14-2011 1:42 PM Jon has replied

  
Jon
Inactive Member


Message 174 of 209 (600468)
01-14-2011 3:32 PM
Reply to: Message 173 by Taq
01-14-2011 1:42 PM


Re: Continuity of the Species
The data shows that there was discontinuity between the populations for 300,000 years.
Perhaps you can make references to the data you believe show this discontinuity, as well as how this discontinuity is relevant in the MH-OOA discussion?
It wasn't until populations migrated out of Africa that these genomes came into contact again, and even then the interaction was very limited resulting in the 5% of non-African DNA in modern populations.
The migration is yet to be supported. Furthermore, I've repeatedly addressed the error of using the percentage of modern, surviving regionally continuous traits to infer the percentages of initial contributions of these populations and the degree to which archaic populations can be considered physically ancestral to modern populations.
Also, why is there only a small amount of surviving non-African DNA? Shouldn't we find a lot more?
Also something I've addressed several times now. Given the size and density of African (central) populations compared to the peripheral populations (Europe, Asia), it is no surpriseeven with an MH modelto find a higher proportion of African genetic material in the world population. This, along with the continued bombardment of peripheral populations by African DNA and the higher selection pressures (driven by the population size and density differences, among other things) for 'modern' traits, makes a modern dominance of African DNA perfectly reasonable within either an OOA or MH model. The amount present we find of non-African DNA depends on how long these factors have been at play and the strength of their effect on selection processes.
Jon writes:
Taq writes:
Our genomes are direct records of the past.
Absolutely false. I've demonstrated already that this is not the case.
So what part of our genome was not inherited from an ancestor?
I don't believe I ever implied that the case was otherwise. Your statement appeared to be a claim that genetic evidence is direct evidence of population histories. I've demonstrated that genetic evidence is partially evidence of the genetic histories of a species, not evidence of the population histories. We cannot use present genetic distributions to infer past population movements/histories. At some time, our model for the past must make some reference to substantial evidence from that past. You can't be a laboratory historian.
So what evidence, in your eyes, would support it? More importantly, what evidence would falsify the MR model as the major mechanism for the evolution of modern humans?
Glad you asked! One possible method, especially regarding regional continuity, would involve examining skeletal/genetic remains in various regions of the world.
Assuming an migration+interbreeding model: any halflings that result from interbreeding will be 50/50 carriers of sapiens and pre-sapiens genetic material and should be the oldest hybrids found in a region. If our model is mostly migration with limited interbreeding, then we should find these locations of 'halflings first' to be spotted around the Old World following the lines of migration.
Assuming a mostly gene-flow model with little migration: the earliest hybrids in the region will not be 'halflings', per se, but will be characterized by a higher proportion of pre-sapiens traits and a lower proportion of sapiens traits, with each later generation showing a higher proportion of sapiens characteristics than the generation(s) previous. If our model is mostly gene flow, then we should find 'halflings first' only at the genetic contact point between the non-originator populations and originator-of-the-DNA populations, and the further out we go from this point of contact, the lower the proportion of sapiens traits in the oldest hybrids will be.
I will definitely take a look at those articles and any others that are cogent.
Do enjoy!
Jon

Check out No webpage found at provided URL: Apollo's Temple!
Ignorance is temporary; you should be able to overcome it. - nwr

This message is a reply to:
 Message 173 by Taq, posted 01-14-2011 1:42 PM Taq has replied

Replies to this message:
 Message 175 by Taq, posted 01-14-2011 4:05 PM Jon has replied

  
Jon
Inactive Member


Message 176 of 209 (600503)
01-14-2011 8:36 PM
Reply to: Message 175 by Taq
01-14-2011 4:05 PM


Re: Continuity of the Species
Also, if MH is true then we shouldn't have divergent genomes to begin with, but we do.
I've repeatedly mentioned why divergence of the type we have isn't a problem for MH.
Likewise, neanderthals split from the modern human lineage at about this time. There were at least 3 human populations with highly restrictive to no gene flow for 300,000 years prior to the proposed migration of Africans into Asia and Europe.
The article doesn't mention how this figure is derived.
So what would the population differences need to be in order for this to work with an MH model?
About what we would expect them to be given the time period and environmental conditions:
quote:
Wolpoff & Caspari in Race and Human Evolution:
Prehistoric population sizes were dramatically larger in Africa (the center) than in the rest of the world, possibly by as much as an order of magnitude. (1997, p. 302)
Also, why would African alleles that are specialized for the open savannas of Africa be selected for in Asia?
Were they?
On top of that, why would selectively neutral traits such as the protruding chin be selected for? That doesn't seem to jive.
I'm not sure the protruding chin feature is the same for all modern humans, or that it's not just a simple architectural compensation/tag-along trait for other skull changes related to brain size. Comparisons of early erectus, late erectus, and Neanderthal varieties all show a steady progression toward a more pronounced chin.
Jon writes:
We cannot use present genetic distributions to infer past population movements/histories.
I think we will have to agree to disagree on this one.
Perhaps we will, but the entire OOA argument rests on the assumption that we can. Thus, I think it important to be discussed further than an agreement for disagreement. Though, I'm willing to let this rest if you'd like to discuss other things of interest related to the two models, such as skeletal morphology, behavioral evidence, etc.
Jon
__________
Wolpoff, M. & R. Caspari. (1997) Race and Human Evolution. New York: Simon & Schuster.

Check out No webpage found at provided URL: Apollo's Temple!
Ignorance is temporary; you should be able to overcome it. - nwr

This message is a reply to:
 Message 175 by Taq, posted 01-14-2011 4:05 PM Taq has not replied

  
Jon
Inactive Member


Message 178 of 209 (600644)
01-15-2011 11:18 PM
Reply to: Message 177 by Blue Jay
01-14-2011 11:04 PM


Re: Continuity of the Species
It's official: this discussion has turned me into Straggler. That is my cue to get out while I can. I deem you hopeless anyway. Unorthodoxy seems to be a hobby with you, and there is nothing to be gained by trying to get you to accept the orthodox view of anything.
I assure you, you've a long ways to go till you turn into Straggler!
I'm glad you stuck around while you could stand it. I think it best to avoid any discussion once it's been labeled as a battle of orthodoxies, so I'm more than pleased to set our disagreement to rest.
All the best!
Jon

Check out No webpage found at provided URL: Apollo's Temple!
Ignorance is temporary; you should be able to overcome it. - nwr

This message is a reply to:
 Message 177 by Blue Jay, posted 01-14-2011 11:04 PM Blue Jay has not replied

  
Jon
Inactive Member


Message 180 of 209 (624702)
07-19-2011 1:28 PM
Reply to: Message 179 by Blue Jay
07-19-2011 12:49 PM


Re: New evidence
Thank you for the link!
quote:
Yotova, et al. in X-Linked Haplotype (abstract):
Our analysis of 6,092 X-chromosomes from all inhabited continents supports earlier contentions that a mosaic of lineages of different time depths and different geographic provenance could have contributed to the genetic constitution of modern humans. (emphasis added)
This part seems central. It is difficult to say more without looking at the article itself, but it would appear that their conclusion of an 'early admixture between expanding African migrants and Neandertals prior to or very early on the route of the out-of-Africa expansion' is not properly supported by this evidence.
The authors apparently want to interpret the findings as pointing to an early one-off admixture consistent with a single migration event. However, it is difficult to understand how this can be reconciled with 'a mosaic of lineages of different time depths and different geographic provenance'.
On top of this, these findings verify a prediction of the MH model and are supported by the OOA model only through the introduction of further ad hoc explanation.
Anyone still attempting to hold to anything even resembling a strict OOA model is no longer doing science.
Jon
__________
Yotova, V., et al. (2011) "An X-Linked Haplotype of Neandertal Origin Is Present Among All Non-African Populations" Molecular Biology and Evolution. Vol. 28, pp. 1957—1962. Abstract.
Edited by Jon, : Emphasis added

Love your enemies!

This message is a reply to:
 Message 179 by Blue Jay, posted 07-19-2011 12:49 PM Blue Jay has replied

Replies to this message:
 Message 181 by Dr Jack, posted 07-20-2011 6:40 AM Jon has not replied
 Message 182 by Blue Jay, posted 07-20-2011 1:36 PM Jon has replied

  
Jon
Inactive Member


Message 184 of 209 (624904)
07-20-2011 4:25 PM
Reply to: Message 182 by Blue Jay
07-20-2011 1:36 PM


Re: Colors in a Mosaic
This demonstrates that, even within a mosaic, there are frequently dominant patterns. For instance, I would have no qualms about calling this mosaic blue, even though there seem to be a couple of tiles in the mosaic that are white.
The specifics of where the genetic material in modern humans comes from is not really of concern to the model of MH. The main claim of MH is that the material will not all be found to have come from the same place. Even if a lot of it comes from one place (which is actually to be expected given the distribution of early humans), the MH model still holds.
These authors are saying that, even though the bulk of the evidence suggests a pattern of blue tiles, they have uncovered at least one white tile. They go on to say that, despite this, the mosaic still rather appears to be blue. From my standpoint, this seems a relatively uncontroversial thing for them to say.
What they are actually doing is stealing large parts of the MH model, labeling them OOA, and then declaring victory for the OOA model and defeat of the MH model.
I find it illustrative to point out that these findings also verify a tenet of the creationist argument concerning Neanderthals as degenerate humans.
And a strict OOA model would support a Creationist arguing that Neanderthals are part of Satan's plot to lead folk from the 'Truth'.
So we best not rely on creationists to steer us where we need go.
Jon

Love your enemies!

This message is a reply to:
 Message 182 by Blue Jay, posted 07-20-2011 1:36 PM Blue Jay has not replied

Replies to this message:
 Message 186 by Dr Jack, posted 07-21-2011 4:44 AM Jon has replied

  
Jon
Inactive Member


Message 185 of 209 (624905)
07-20-2011 4:32 PM
Reply to: Message 183 by New Cat's Eye
07-20-2011 1:54 PM


Re: Colors in a Mosaic
Hi bluejay,
In Message 108, you wrote:
quote:
It seems silly to me to formulate a theory about biology---a field in which essentially all data sets are messy---so that it can't tolerate any deviance from 100% purity.
This seems like what the new MR-proponents are doing: they're arguing that any deviance from the most stringent interpretation of OoA is vindication of MR.
In light of new evidence, in Message 180, Jon writes:
quote:
On top of this, these findings verify a prediction of the MH model and are supported by the OOA model only through the introduction of further ad hoc explanation.
Anyone still attempting to hold to anything even resembling a strict OOA model is no longer doing science.
I don't see that my argument is at all the same as what Bluejay said 'new MR-proponents are doing'. I don't think anything is a 'vindication of MR', this new evidence included.
I think this evidence verifies one of the MH predictions and forces the OOA model into ad hoc mode. Verifying predictions is one of the ways science strengthens theories. But it in no way vindicates them.
Jon

Love your enemies!

This message is a reply to:
 Message 183 by New Cat's Eye, posted 07-20-2011 1:54 PM New Cat's Eye has not replied

  
Jon
Inactive Member


Message 187 of 209 (625071)
07-21-2011 10:09 AM
Reply to: Message 186 by Dr Jack
07-21-2011 4:44 AM


Re: Stop making up what the MRH says!
That is what the multi-regional hypothesis says! It claims that essentially parallel evolution occurred around the world, with a continuation of morphological features across tens of thousands of years.
Sounds more like you are describing polygenesis.
MH describes an interconnected evolving species; traits arise in various locations and spread throughout the rest of the world population.
... but a much more complete claim of evolution occurring locally within human lineages.
Not really. Central features are expected to flood the population as a whole, over time 'diluting' out regional differences which become less prominent as the species evolves.
This, of course, is according to Milford Wolpoff, the leading expert on, and proponent of, MH; but what does he know, eh? You found the Wiki!
Jon

Love your enemies!

This message is a reply to:
 Message 186 by Dr Jack, posted 07-21-2011 4:44 AM Dr Jack has replied

Replies to this message:
 Message 188 by Blue Jay, posted 07-21-2011 12:37 PM Jon has replied
 Message 198 by Dr Jack, posted 07-22-2011 4:10 AM Jon has replied

  
Jon
Inactive Member


Message 189 of 209 (625115)
07-21-2011 1:15 PM
Reply to: Message 188 by Blue Jay
07-21-2011 12:37 PM


Re: Stop making up what the MRH says!
If you restrict your opponents to the strictest form of their model, isn't it only fair for your opponents to restrict you to the same?
The 'strict' OOA model is simply the OOA model first proposed. No one is forced to hold to this strict version, especially given the evidence that has been found since its development. But they will then have to admit that their new version is just the older version supplemented with excessive ad hoc explanations.
Until all the ad hoc came about, strict OOA was the only OOA. And this is my point, the non-strict OOA is full of ad hoc.
The strict MR model is essentially what Mr Jack described. It states that regional populations of modern humans are genealogically continuous with archaic populations of the same regions. It argues that Europeans are essentially Neanderthals, Asians are essentially erectines (or Denisovans), and Africans are Homo sapiens sapiens. It differs from strict polygenism in that it allows genetic admixture between populations. But, it predicts that only those traits that are universally beneficial will have spread, while traits that are neutral or only regionally beneficial will not have spread.
This is not the theory described by Wolpoff and his ilk. This is not the theory I've been arguing for.
Surely you can agree that this strict MR model does not hold up to scrutiny?
What you call a 'strict MR model' has not been argued for in any serious academic setting for decades.
Essentially, once it was falsified in its strictest form,
The strict form you describe was falsified decades ago; the evidence that led to its falsification is the evidence that led to the development of the modern (actual) MH model.
Even worse, you're attempting to argue that even a softened out-of-Africa hypothesis is invalidated by this new evidence of admixture.
I never said anything was invalidated. This is a point I've made repeatedly regarding the scientific method, in this thread and in others.
It's really about time to stop misrepresenting me.
You seem to believe that any deviation from the strictest out-of-Africa model vindicates the stronger claims of the old multiregional model,
No; I don't. I've also spoken against this stupid notion of 'vindication' multiple times in this thread and others.
It's really about time to stop misrepresenting me.
I hope this provides some insight into why Mr Jack and I have gotten so irritated with you about this.
Probably because you both think I'm arguing for a position for which I am not actually arguing; a position which, you yourself admit, is 'something that modern MR proponents don't even claim'.
Of course, this debate is between you and me; so what other people argue regarding the two theories is irrelevant to the positions we present, which is why I've never held anyone here to the strict OOA model.
Jon

Love your enemies!

This message is a reply to:
 Message 188 by Blue Jay, posted 07-21-2011 12:37 PM Blue Jay has replied

Replies to this message:
 Message 190 by Blue Jay, posted 07-21-2011 3:02 PM Jon has replied

  
Jon
Inactive Member


Message 191 of 209 (625148)
07-21-2011 3:33 PM
Reply to: Message 190 by Blue Jay
07-21-2011 3:02 PM


Re: Stop making up what the MRH says!
You argue that evidence of genetic admixture leads to the rejection of migration as a tenable explanation for anything.
Not really. My argument is that there is no evidence that supports a migration. You quoted this sentiment from two of my posts:
quote:
Jon in Message 26:
OOA makes specific claims about population movements; these claims cannot be supported by the current evidence.
quote:
Jon in Message 24:
Genetically speaking, modern sapiens are of African origin. I do not wish to dispute this. The issue is concluding physical origin on the basis of genetic origin. This is a conclusion I do not find overly validated by the information available.
The migration model is unnecessary to explain modern genetic distributions.
The gene flow and regional continuity model is necessary to explain modern genetic (and morphological) distributions.
These recent findings (the one this thread was started about, the one you recently linked to, and others) have added support to the necessity of the latter model. As far as I'm aware, aside from the initial computer analyses, no findings have yet shown the former model to be necessary.
Or, when was the last time any extra evidence was found adding support to the necessity of the OOA model? The theory still seems to rest on those same outdated erroneous computer models upon which it was founded years ago.
Why it is still touted as a necessary explanation is beyond me.
Jon
BTW: Something's wrong with your message linkes; perhaps you meant to use the /msg/ tag instead of the /mid/ tag?
Edited by Jon, : No reason given.
Edited by Jon, : No reason given.

Love your enemies!

This message is a reply to:
 Message 190 by Blue Jay, posted 07-21-2011 3:02 PM Blue Jay has replied

Replies to this message:
 Message 193 by Blue Jay, posted 07-21-2011 4:38 PM Jon has replied

  
Jon
Inactive Member


Message 194 of 209 (625201)
07-21-2011 7:27 PM
Reply to: Message 192 by Blue Jay
07-21-2011 4:19 PM


Re: Multiregional hypothesis
Here and here are two such papers.
The links don't seem to have come through there; but I would be interested in reading the papers if you have the links.
ABE: It seems the links are in the Peek message but didn't parse right in the final post. Gonna look into the papers and let you know what I think./ABE
Milford H. Wolpoff, one of multiregionalism's strongest proponents from the 1980's until today, wrote several papers about the hypothesis. He seemed to only be concerned with chastising misconceptions about the hypothesis, and, as far as I have been able to determine, never actually got around to explaining what, exactly, the hypothesis did say.
Wolpoff has written two books that I have read, and likely others, regarding human evolution. One of those books, Race and Human Evolution, is concerned almost exclusively with the development and nature of MH; the other is a general text book that gives considerable space to the MH model.
For instance, Wolpoff (and co-authors) is insistent that MR does not predict that there would be more genetic and morphological heterogeneity at the "crossroads" of the regional populations than at the peripheries. Yet, as far as I can tell, this should be an unavoidable result of the MR hypothesis as he explains it.
If you can get a hold of the Race and Human Evolution book, he deals with the issue of 'center and edge', as he calls it, over the span of several pages.
He also claims that MR does not predict that there would be fossils showing hybrid gradients between regional populations.
I've read several pieces of work by Wolpoff where he deals with, argues for, and presents examples of, hybrid forms.
He also discusses two interpretations of the MR model that he regards as inaccurate: the "multiple origins" model (in which modern regional populations are descended from archaic populations of the same region) and the "parallel evolution" model (in which traits common to different regional populations evolved separately). My confusion lies in the fact that one or the other, of necessity, must be true, at least to some extent, in order for MR to meaningfully explain anything.
Without seeing his exact words, I cannot be certain of the accuracy of these claims. This doesn't sound like anything I've read in his work.
Also, in this paper, he proposed regional continuity in Australasian fossil morphology as evidence of MR, then claims in the first paper cited above the MR does not necessarily predict regional continuity.
Again; if you can get the links posted, I can address the issue you've brought up.
"Somebody banged a Neanderthal" seems an awfully vague prediction for such a grandiose hypothesis to make.
And MH doesn't make any prediction that 'somebody banged a Neanderthal'.
Jon
Edited by Jon, : ABE

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This message is a reply to:
 Message 192 by Blue Jay, posted 07-21-2011 4:19 PM Blue Jay has replied

Replies to this message:
 Message 203 by Blue Jay, posted 07-25-2011 11:18 AM Jon has not replied

  
Jon
Inactive Member


Message 195 of 209 (625202)
07-21-2011 7:43 PM
Reply to: Message 193 by Blue Jay
07-21-2011 4:38 PM


Re: Modern genetic distributions
Migration is a much better explanation for the wholesale takeover of one gene pool with genes from another than is passive genetic diffusion through hybridization.
But we already know that 'passive genetic diffusion' took place, as demonstrated by the evidence presented in this thread. There is, therefore, little reason to suppose a further mechanism when we've already evidence of a perfectly suitable mechanism at work.
that their genes diffused virtually unmolested throughout all of the world through hybridization while the archaic Africans themselves stayed in Africa.
There is nothing in MH about unmolested genes. In fact, quite the contrary; MH would predict that the first wave of gene outflow would show up on the peripheries as being highly 'molested'. However, a continued outflow would eventually lead to the central genetic information overtaking the regional genetic information; each outflow would leave behind less peripheral genetic information in its wake, especially if the outflow involved genes carrying beneficial adaptations.
There is no conceivable reason why a model that proposes regional adaptations and extensive hybridization would result in such lopsided dominance by haplotypes from Africa.
I've mentioned several times in this thread why we would see 'lopsided dominance'. See the paragraph above this one for a brief overview of my position on this.
MR is simply too grandiose a model to seriously explain the distribution of genes in modern human populations.
There's nothing grandiose about it. It's actually quite cozy.
Jon

Love your enemies!

This message is a reply to:
 Message 193 by Blue Jay, posted 07-21-2011 4:38 PM Blue Jay has replied

Replies to this message:
 Message 205 by Blue Jay, posted 07-25-2011 12:02 PM Jon has replied

  
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