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Author Topic:   40k-Year-Old Man Had Recent Neanderthal Ancestor
Jon
Inactive Member


Message 1 of 25 (760601)
06-23-2015 5:11 PM


Apparently a man who lived only forty thousand years ago had Neanderthal ancestors only a few generations back.

quote:
"Early Man from Romania Had Close Neanderthal Relatives, DNA Shows" from L A Times:

A new discovery, announced Monday in the journal Nature, adds a piece to the puzzle. DNA testing of an ancient jawbone has confirmed that a man who lived in Romania about 40,000 years ago descended from a Neanderthal ancestor just four to six generations – less than 200 years – before him.

"To our amazement, this guy had three or four times more Neanderthal DNA than any modern human we had ever looked at," said Svante Paabo, director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and co-senior author of the Nature study. "This is the first time we can say it's dramatically more, and close in the family tree."


Genetic evidence has been the basis of the OOA model of human origins and is usually considered standing in contrast to the physical evidence which supports the Multiregional model.

But some of these new findings (see the other thread: New Type of Ancient Human Found—Descendants Live Today? ) show us that the genetic evidence, when considered in its entirety, is more likely going to end up supporting the MH model than it will the OOA model (which is now as full of holes as Swiss cheese).


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Replies to this message:
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Jon
Inactive Member


(1)
Message 4 of 25 (760605)
06-23-2015 6:37 PM
Reply to: Message 3 by jar
06-23-2015 6:19 PM


Re: Not sure how this could be in conflict with OOF
I can live with that.

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Jon
Inactive Member


Message 6 of 25 (760608)
06-23-2015 7:25 PM
Reply to: Message 5 by AZPaul3
06-23-2015 6:58 PM


I don't see how a population of H. neanderthalensis known to exist at 35k years ago and a population of H. sapiens known to be in the same region at the time conflicts with Out-Of-Africa. What this evidence shows is that the gene flow between the populations may have continued more recently than previously hypothesized.

The issue of interbreeding was discussed in the other thread (linked to in the OP). But basically, the OOA tree model fails to account for the fact that while we carry recent African-origin genetic material we also carry genes of recent non-African origin, which is and always has been the MH position.

The fact that this person's material didn't make it into today's gene pool also supports the MH explanation that the paucity of lineages outside of Africa results from lineage extinctions.

The question now is why, with such recent crossings, is there not more neanderthal DNA in present sapiens populations.

According to the article, the individual in question is not an ancestor of any modern human populations.


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Jon
Inactive Member


Message 8 of 25 (760620)
06-23-2015 9:47 PM
Reply to: Message 7 by Coyote
06-23-2015 7:55 PM


This sure beats measuring bones, as we used to have to do a couple of decades ago to try and determine relationships.

It may beat it, but let's hope it doesn't replace it!


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Jon
Inactive Member


Message 13 of 25 (761248)
06-29-2015 8:52 PM
Reply to: Message 10 by caffeine
06-29-2015 11:25 AM


Of course, there is no way that could be known.

I assumed the article meant that no known sequences from today have the characteristics expected in an ancestor of this individual.

...since modern populations in Europe and Asia seem to have inherited only a minority of their genes from the middle Palaeolithic inhabitants of Europe and Asia.

I think you mean that modern populations in Europe and Asia seem to have preserved only a minority of their Neanderthal genes.

The genetic signature of these archaic populations was mostly swamped by the expanding Africans - except for a few genes, most of which presumably were locally adaptive.

Or they were just swamped by the expanding African genes...

Edited by Jon, : No reason given.


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Jon
Inactive Member


Message 17 of 25 (761493)
07-01-2015 8:17 PM
Reply to: Message 15 by caffeine
07-01-2015 12:56 PM


Or they were just swamped by the expanding African genes...

That's a better way of saying what I was trying to say, though!

I'm glad you think so. Because the difference is the essence of the difference between MH and OOA.

MH explains the evolution/distribution of modern Homo sapiens as largely a product of gene movement.

OOA explains the evolution/distribution of modern Homo sapiens as largely a product of people movement.

Edited by Jon, : codes...


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Jon
Inactive Member


Message 18 of 25 (761494)
07-01-2015 8:24 PM
Reply to: Message 16 by Taq
07-01-2015 1:15 PM


The two models have never been mutually exclusive. If about 5% of our genomes are from crossbreeding and the other 95% from our African ancestors, then the MH model explains 5% of our genome and the OOA model explains 95% of our genome.

It's a bit like the "argument" between gradualism and punctuated equilibria. You can have both.

I think MH works fine with the observation that 95% of our genome is African while 5% is from sources outside of Africa.

Where the theories differ is in explaining why that distribution exists. MH explains it as a result of African genes swamping non-African ones (the genes were superior, more numerous, etc.) with little need for the large population movements posited by OOA.

MH works as an explanation for the genetic evidence, to be fair, OOA does too, but MH has the added benefit of explaining the physical evidence and matters such as regional continuity of completely random traits.


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Jon
Inactive Member


Message 20 of 25 (761590)
07-02-2015 9:02 PM
Reply to: Message 19 by caffeine
07-02-2015 2:42 PM


The idea of genes moving without any significant movement of populations was sufficient to explain the fact the mtDNA had a recent African origin, but if we're talking more than 90% of the genome it doesn't seem reasonable to think this happened without lots of people carrying these genes.

More than 90% of which genome? The fella in question wasn't 90% African.

The 90% African distribution is the result of millennia of gene flow out of Africa.

But why should the selectively neutral bits of the genome from Africa come to dominate everywhere without being carried by an expanding African population?

Whether the dominance of African genes was brought about by migration or breeding, the evidence rather suggests that the African genes were anything but 'neutral'—they're the genes that won.


Love your enemies!

This message is a reply to:
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Jon
Inactive Member


Message 22 of 25 (761764)
07-05-2015 9:22 AM
Reply to: Message 21 by caffeine
07-05-2015 5:31 AM


So, you're proposing not one large population expansion in the last hundred thousand years, but a continually expanding African population?

No; I am 'proposing' (actually just repeating what countless scientists have proposed) a continual expansion of African genes.

How is this simpler?

It's not. It's messy and complicated like real life.

But unless you're suggesting that there is no such thing as a selectively neutral difference the dominance of African alleles cannot be due solely to selection.

The African genes were clearly superior; both theories recognize this fact.


Love your enemies!

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