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#15574 - 10/11/06 04:53 PM Neanderthal DNA illuminates split with humans
DA Morgan Offline
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The first comparison of human and Neanderthal DNA shows that the two lineages diverged about 400,000 years ago and that Neanderthals may have had more DNA in common with chimps than with modern humans.

There is ongoing debate over whether the Neanderthals were a separate species, Homo neanderthalensis, or a subspecies of Homo sapiens. The first Neanderthals are thought to have emerged about 350,000 years ago, so the new findings from this DNA analysis strongly favour the theory that modern humans and Neanderthals share a common ancestor but are not more closely related than that.

For more:
http://www.newscientist.com/article/dn10275-neanderthal-dna-illuminates-split-with-humans.html
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#15575 - 10/12/06 02:37 AM Re: Neanderthal DNA illuminates split with humans
terrytnewzealand Offline
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I would be very interested to read the actual paper if you can find it. It will not be a simple matter for the scientists to find any appropriate genes. NZ scientists are having trouble finding the difference between holstein and jersey cattle genes. They're working backwards by looking at the F2 and F3 hybrids.

The half million year's separation mentioned in the article is the mitochondrial DNA lines, about the time Homo heidelbergensis began their expansion.

The same mtDNA time scale puts the separation between cattle and bison as twice as long, a million years. Althoughn speciation is unlikely to be simply a function of time hybrids between cattle and bison are fertile. Incidentally, does anyone know anything about domestic cattle ever joining bison herds?

The myDNA evidence on its own is not sufficient to prove no Neanderthal genes survive in modern humans. It would be interesting to know how the scientists chose the genes they looked for. They would be unlikely to find Neanderthal genes in Africans or Polynesians for example. My bet would be that if they have concentrated on stocky Europeans with big noses, blond hair and a tendency for a bulge at the back of their skull they would raise their chances.

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#15576 - 10/12/06 12:57 PM Re: Neanderthal DNA illuminates split with humans
soilguy Offline
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Terry:

This study was done on nuclear DNA, not mtDNA. As I recall (and I don't have a photographic memory), mtDNA studies put the split between the species further back in time.
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#15577 - 10/13/06 01:29 AM Re: Neanderthal DNA illuminates split with humans
terrytnewzealand Offline
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No, no soilguy. The article DA posted doesn't say what parts of the nuclear DNA they looked at. That's why their own publication would be most interesting. Mitochondrial DNA studies all have the split at 350,000 to 400,000 years so nothing new in this release as yet.

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#15578 - 10/13/06 12:55 PM Re: Neanderthal DNA illuminates split with humans
soilguy Offline
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Terry,

So what? All I said was that they looked at nuclear DNA, not mtDNA, in this study.
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#15579 - 10/13/06 10:14 PM Re: Neanderthal DNA illuminates split with humans
terrytnewzealand Offline
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Soilguy, you might find this interesting:

http://cogweb.ucla.edu/ep/Templeton_02.html

Of course there is nothing specifically Neanderthal covered but it does show hybridising between Out of Africa and pre-existing human populations.

In my observation the belief in replacement by a single movement "Out of Africa" in influenced by biblical stories about species, including humans, descending from a single couple. We know evolution involves whole populations. Have you had intimate contact with some subspecies of the Judeo-Christian genus of human belief?

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#15580 - 10/13/06 10:27 PM Re: Neanderthal DNA illuminates split with humans
terrytnewzealand Offline
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Another one. Covers much the same ground but amplifies the ideas a little:

http://dienekes.blogspot.com/2006/02/alan-templeton-vs-out-of-africa-with.html

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#15581 - 10/14/06 03:40 PM Re: Neanderthal DNA illuminates split with humans
soilguy Offline
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Soilguy, you might find this interesting:

http://cogweb.ucla.edu/ep/Templeton_02.html

Of course there is nothing specifically Neanderthal covered but it does show hybridising between Out of Africa and pre-existing human populations.


I have no problem with the idea of multiple emigrations out of Africa. There just doesn't seem to be evidence of interbreeding with Neandertals.

In my observation the belief in replacement by a single movement "Out of Africa" in influenced by biblical stories about species, including humans, descending from a single couple. We know evolution involves whole populations. Have you had intimate contact with some subspecies of the Judeo-Christian genus of human belief?

Judeo-Christian stories are meaningless to this question, in my opinion. I have no stake in whether we (Homo sapiens) interbred with Neandertals or not, if that's what you're asking. I'm only interested in what the pertinent researchers think, and the reasoning behind their thinking. It just seems to me that the genetic evidence that we have to date is contrary to the idea that there was interbreeding between the two types of humans, since the dawn of Homo sapiens.
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#15582 - 10/14/06 05:58 PM Re: Neanderthal DNA illuminates split with humans
DA Morgan Offline
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Soilguy is correct TTBOMK. I am not aware of any reports supporting interbreeding.

No doubt we reacted to them the way we react to each other: Genocide.
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#15583 - 10/15/06 12:25 AM Re: Neanderthal DNA illuminates split with humans
terrytnewzealand Offline
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Strange that it seems it was only in Europe that modern humans committed genocide against the pre-modern human inhabitants. Was that an indication of the future?

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#15584 - 10/15/06 01:22 AM Re: Neanderthal DNA illuminates split with humans
samwik Offline
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Re: "I have no problem with the idea of multiple emigrations out of Africa. There just doesn't seem to be evidence of interbreeding with Neandertals." from -soilguy (I think?)

Anyway, I haven't looked at the links yet but do any of them refer to how all the populations that left Africa before 70,000 yr. ago were probably wiped out by the big volcano back then. Was it Tambura, in Indonesia? I'll go check the web, but there was a sort of "nuclear winter" back then which would explain why our diversity mainly traces back 70,000, except within Africa. Neanderthals probably did survive, being far enough away and better adapted. Basically, they could easily be the only 'out of Africa' group, from our lineage, that survived the volcano.
~Sam
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#15585 - 10/15/06 01:47 AM Re: Neanderthal DNA illuminates split with humans
samwik Offline
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Update: Nope, it was Toba; not Tambora.
~Sam

35 x 100 km Toba caldera, the Earth's largest Quaternary caldera, was formed during four major Pleistocene ignimbrite-producing eruptions beginning at 1.2 million years ago. The latest of these produced the Young Toba Tuff (YTT) about 74,000 years ago. The YTT represents the world's largest known Quaternary eruption, ejecting about 2500-3000 cu km (dense rock equivalent) of ignimbrite and airfall ash from vents at the NW and SE ends of present-day Lake Toba. Resurgent doming forming the massive Samosir Island and Uluan Peninsula structural blocks postdated eruption of the YTT. Additional post-YTT eruptions include emplacement of a series of lava domes, growth of the solfatarically active Pusukbukit volcano on the south margin of the caldera, and formation of Tandukbenua volcano at the NW-most rim of the caldera. Lack of vegetation suggests that this volcano may be only a few hundred years old (Chesner and Rose, 1991).

...and speaking of climate change....
Does anyone know the "volcano equivalent" of anthropogenic pollution?
~Sam
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Pyrolysis creates reduced carbon! ...Time for the next step in our evolutionary symbiosis with fire.

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#15586 - 10/15/06 02:51 AM Re: Neanderthal DNA illuminates split with humans
terrytnewzealand Offline
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Samwik. Home erectus survived in Southeast Asia until possibly as recently as 30,000 years ago. This is quite near the centre of the eruption and so I doubt the destruction of humanity, or life in general, was as severe as some scientists like to make out.

Re. the studies. They show that modern human genes include some that show a regional origin from over the last 1.7 million years. These variations would not show up regionally if humans genes all came out of Africa in one go at any time since then. But as the writers on the paper on the split between humans and chimpanzees (another post, I forget which) say it may take a long time before their evidence is accepted.

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#15587 - 10/15/06 02:58 AM Re: Neanderthal DNA illuminates split with humans
terrytnewzealand Offline
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Samwik. For your interest and edification here is the chimpanzee site again. I've earlier put it in the "Out of Asia - not Africa" on the science discussion forum but it won't hurt to put it in again.

http://www.haverford.edu/KINSC/06Journal/nature04789.pdf#search=%22genetic%20evidence%20for%20complex%20speciation%20of%20humans%20and%20chimpanzees%22

.

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#15588 - 10/15/06 03:36 AM Re: Neanderthal DNA illuminates split with humans
samwik Offline
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Yes, and the hobit florensis folks too, I guess. And I should have made it clear that i was talking mostly conjecture or barely hypothetical. Thanks, I'll look at these links.
~Sam
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Pyrolysis creates reduced carbon! ...Time for the next step in our evolutionary symbiosis with fire.

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#15589 - 10/15/06 04:36 AM Re: Neanderthal DNA illuminates split with humans
samwik Offline
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Couldn't get that lastlink, but here's an interesting one.
http://human-nature.com/nibbs/02/frost.html

Even if neanders are closer to chimps than us, that'd still mean they were less than 1% different; wouldn't it?
~Sam
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Pyrolysis creates reduced carbon! ...Time for the next step in our evolutionary symbiosis with fire.

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#15590 - 10/15/06 09:07 AM Re: Neanderthal DNA illuminates split with humans
terrytnewzealand Offline
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Thanks samwik. Good overall look at the situation. Do you not have acrobat reader? You can download it reasonably easily. You can then read PDF files.

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#15591 - 10/17/06 03:46 AM Re: Neanderthal DNA illuminates split with humans
terrytnewzealand Offline
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Samwik, I've read your contribution again and I note:

"In the absence of selection pressures, the current level of hair colour diversity would have taken 850,000 years to develop (Templeton 2002). One would have to conclude that the gene pool of Eastern and Northern Europe is derived mainly from the Neanderthals and even earlier Homo populations. Otherwise, some kind of selection must have favoured these colour polymorphisms."

Interestingly the possibility is immediately disregarded as it doesn't fit the paradigm. The large number of genes contributing to blond hair also indicates a very long period of diversification. When examined the sexual selection explanation falls to pieces. The evidence is more likely to indicate a movement of modern humans into Europe gradually replacing genes for blond hair.

This takes us back to a comment soilguy made:
"Judeo-Christian stories are meaningless to this question, in my opinion."

Soilguy, I was merely pointing out the obvious, that our pre-existing beliefs always influence how we interpret evidence. The Judeo-Christian myths are so deeply embedded in western culture that even atheists are influenced by them.

I don't know if you have read books by Stringer, Olson or Tattersall. Their books are crammed with biblical ideas. They ask such questions as "Why were we the chosen ones?", "What made us so special?" etc. By this argument Tasmanian Aborigines were not human. Australian Aborigines and North American Indians are barely so.

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#15592 - 10/17/06 04:17 AM Re: Neanderthal DNA illuminates split with humans
samwik Offline
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I haven't looked into this much, but I'm sure I've heard that it only took about 20,000 years for skin color to change from dark to light (Arican to N.European). But that is with some selection pressures such as the vitamin D/Folic acid paradox. Maybe 850,000 yr. is right, but are there ever no selection pressures?
~Sam
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Pyrolysis creates reduced carbon! ...Time for the next step in our evolutionary symbiosis with fire.

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#15593 - 10/17/06 07:00 AM Re: Neanderthal DNA illuminates split with humans
terrytnewzealand Offline
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There is probably almost never no selection pressures. The problem is: what was the selection pressure? From the article you posted we see it's accepted humans in the northern regions ate a lot of meat. This provides vitamin D. Therefore no selection pressure for white skin from that angle.

So-called white people actually turn brown in summer by tanning. For any other creature that had white hair, blue eyes and changed from white to brown with the seasons we'd have no hesitation pronouncing it was an adaption to winter snow. Are we so convinced humans obey a different set of biological rules to all other species that we discount this idea?

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