Cro-Magnon people and Neanderthals may have shared their European habitat from 45,000 to 30,000 years ago, but new evidence suggests that they didn’t get more intimate than that. Italian researchers sequenced mitochondrial DNA from Cro-Magnon bones dating from 28,000 years ago and found no trace of Neanderthal DNA, suggesting that the two early hominids did not interbreed to create modern humans.
The fate of the Neanderthals, who vanish from the fossil record around 30,000 years ago, has been fiercely debated. One theory, known as the Out of Africa hypothesis, holds that modern humans, whose ancestors had recently migrated from Africa, drove the Neandertals extinct, possibly through warfare, disease, or cognitive advantage. But the competing multiregional hypothesis argues that Neandertals and modern humans interbred and that Neandertals were absorbed into our gene pool [ScienceNow Daily News].
The new study, published in the journal PLoS ONE, supports the extinction theory. Lead researcher Guido Barbujani has tried to make this case before: His team published similar findings in 2003, but that study left open the possibility that the Cro-Magnon DNA had been contaminated by the researchers’ own genes. Now, Barbujani’s team has sequenced a section of DNA from everyone who handled the sample and found no trace of contamination. “We knew we had a full and complete list of people who had potentially contaminated the specimen,” he says. “In this case we are really sure that that sequence does not represent contamination” [New Scientist].
Image: flickr/JL2003
July 22nd, 2008 at 9:25 am
[...] mitochondrial DNA from 28,000-year-old Cro-Magnon bones has found no traces of Neanderthal DNA, suggesting that the two early hominids did not interbreed to create modern humans. These findings make it increasingly unlikely that we’ll uncover evidence of a drama [...]
July 31st, 2008 at 12:38 pm
They need more DNA testing, to determine if there was any interbreeding.
George.
August 1st, 2008 at 9:23 pm
Woah. Romeo and Juliet had nothing on them. This girl was cro-magnum.
August 2nd, 2008 at 12:43 pm
OK, they have clear evidence that the reported sample was not contaminated with modern (living) researchers & handlers. If that step is ‘clean’ then we need to get more detailed than a Discover report, if we still don’t ‘believe’ the implications.
Full disclosure: I have never studied DNA testing or methods, and don’t know how it is done. I would appreciate a ref. to a good introductory or intermediate text on the subject, esp. how to compare DNA samples.
The fundamental analytical problem is that we are trying to say, “there is nothing there.” This is a lot harder to prove than “there is something (Neanderthal DNA) there (in Cro-Magnon DNA).” If we must have a negative statement, then we should try to say, “there is no more than X there.” If you think only in terms of yes/no dichotomies, you will have trouble with the above. Sorry ’bout that.
IN the selected section of DNA that the researchers felt was clearly different between the groups:
What is the range (spread) of mitocondrial DNA measurements in Neanderthals, what number and over what geographic range do we have these samples?
How many Cro-Magnon samples did they get, and from what geographic range?
Now I can make a tentative hypothesis, that the selected DNA range is equal in both, and a statistical test will conclude that no, they are not ‘nearly identical’ but radically different. I would conclude from this that, _on average_ the two groups did not mix DNA.
Our question then becomes, “did a number of individuals come from intermixed prior generations?” To answer this, we must look at the ‘outliers’ in the samples – those who were closest to matching the other group. In other words, we need to know the number & spread, and even the distribution, of the Cro-Magnon group (and the Neanderthal group). If we have enough samples, can we see a skewing in the distribution, toward Neanderthal characteristics?
Now, if the measurement is that a characteristic (DNA sequence) is either ‘there’ or ‘not there,’ we have a dichotomy – yes or no. The statistical analysis must be different, and more complex. The fundamental logic will remain the same and the questions will be adjusted only slightly.
George, a commenter 7/31, says they need more DNA testing. Maybe, maybe not. Maybe they only need to explain the analysis in more depth. Perhaps more depth than George, or most other people, would put up with :) The Discover piece has not enough depth to say. It can’t.
Jay
August 3rd, 2008 at 1:58 pm
I don’t understand how a definitive answer to the question can be obtained from *one Cro-Magnon sample*. The fact that one particular Cro-Magnon had no ancestors who interbred with Neanderthals does not prove that ALL Cro-Magnon’s did not–right?
These two forms of humans occupied the same territories over a wide area of the Middle East and Europe–is it not possible that a sample taken elsewhere might indicate interbreeding?
September 7th, 2008 at 1:26 am
What part of “did not” don’t you understand?
This Great Ape, Neanderthal..did not contribute any genes to the ancient or modern human gene pool. That is a proven fact whatever anyone suggests about ‘racial characteristics” of Mongolians or the Germans..and those same people loudly declare they and Darwin are not racist..Ha!?
It is a terrible fairy tale fantasy when this carnivorous Beast is garbed in borrowed “humanity” by supposed scientist..speech, autism, fire, tools, clothes..touted as gentle primitive *humans* who in reality were carnivorous, hairy animals..Beasts whose remains were buried by humans, rituallistically and who scavenged around cold camp fires made by humans, possibly taking tools and then been ascribed as the creator of same..This is the “scientific” equivalent of saying my dog manufactures tennis balls and buries his dead in Forest Lawn Pet Semetary..ain’t he our first cousin or is he really your grandpa? Oh…And My Dog tends the fire in the fireplace..The scientist of the future will determine That by his Teeth Marks on the Sticks in the Yard..
Go read about this ..fantasy human, read all about Neanderthal’s “speech, burials, fires, tools”..a Darwinist fabrication, an absurd story of “grandma Neanderthal”..and now it is exposed for what it is..a big lie, a monstrous myth…and taught in every class room in America..
September 14th, 2008 at 2:06 pm
It seems to me that the findings don’t support the conclusion.
So we have analyses of mDNA from one (1) Neanderthal, and one (1) Cro-Magnon. The CM’s is like our own, and the N’s isn’t.
Remeber, though, this is mDNA. It doesn’t get mixed the way normal DNS does. Absent mutations, your mDNA is exactly the same as your mother’, and in any case it’s completely unrelated to your father’s except insofar as his was already related to your mother’s, that is, via common female ancestors.
45,000 years sound like a lot, but one wouldn’t expect many mDNA mutations in that time, so the fact that the CM’s is very similar to that known from modern humans is entirely unsurprising.
As for the rest – if two people have dissimilar mDNA, that doesn’t prove they’re unrelated: just that they do not have any (close) female ancestors.
So, given that we’re fairly (though by no means absolutely) certain that no modern human has mDNA similar to that Neanderthal, neither it nor any of it’s female ancestors, or descendants of those female ancestors, seem to have made it into modern humans. And none of it’s female ancestors were Cro-Magnons.
However, that’s still only one (1) Neanderthal. We currently have no way to know how similar Neanderthal mDNA usually was. (For that matter, we don’t know that about Cro-Magnons either, but the similarity to ours certainly suggests that the spread might have been similar, too.)
So … how about if M/CM hybrids were usually infertile, like mules? You’d still find first-generation exemplars, but no others.
I’m sure there are still more possibilities … among them, of course, the possibility that interbreeding really didn’t occur.
But it’s much too early to claim we know!
September 30th, 2008 at 10:50 am
ohh shut the hell up
September 30th, 2008 at 10:51 am
shut up
April 6th, 2009 at 1:36 pm
[...] Discover Magazine: “Cro-Magnon people and Neanderthals may have shared their European habitat from 45,000 to [...]
February 22nd, 2010 at 9:04 pm
Neanderthals with their well noted larger brain cases could communicate telepathicly. Holding a great distain for the encroaching Cro-Mags, who did not cut the grass around their caves and performed loud “jungle music”all night long, the telepathicaly inter-joined Neanderthals got their collective hairy asses in gear and quickly developed warp drive as a means of “getting out of Dodge”.
It, however, ia theorized that they eventually inter-bred with the Zeta-Reticulans, another star-faring race.
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