Neanderthal DNA Shows They Rarely Interbred With Us Very Different Humans

By Andrew Moseman | August 8, 2008 10:56 am

Neanderthal DNAFor the first time, scientists have sequenced the mitochondrial DNA of a Neanderthal. Researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, analyzed the genetic material from a 38,000-year-old leg bone found in Croatia and published their findings today in Cell.

The mitochondria are only passed down the female line, so can be used to trace the species back to an ancestral “Eve”, the mother of all Neanderthals. The team analysed the DNA of 13 genes from the Neanderthal mitochondria and found they were distinctly different to modern humans, suggesting Neanderthals never, or rarely, interbred with early humans. The genetic material shows that a Neanderthal “Eve” lived around 660,000 years ago, when the species last shared a common ancestor with humans [Guardian].

It’s difficult to know exactly when one species diverges into two—the sceintists estimated their date by comparing the Neanderthal DNA to that of modern humans, chimps, and bonobos. Starting with the commonly-held idea that chimps and humans diverged six to eight million years ago, and factoring in the rate of mitochondrial DNA evolution, the team dated Neanderthal separation from humans back 660,000 years.

According to John Hawks, a University of Wisconsin-Madison biologist not involved in the study, the work further dispels the idea that modern humans are closely related to Neanderthals. “Comparing the complete mitochondrial DNA genomes of a Neandertal and many recent humans presents a very different picture,” Hawks says. “Humans are all more similar to each other, than any human is to a Neandertal. And in fact the Neandertal sequence is three or more times as different, on average, from us as we are from each other” [Science News].

However, much remains to be learned about Neanderthal DNA: The mitochondrion – a structure often dubbed the cell’s powerhouse – contains a mere 16,565 DNA letters that code for 13 proteins, whereas the nucleus holds more than 3 billion letters that produce more than 20,000 proteins [New Scientist]. Still, study leader Richard Green says he hopes to be well on the way to a complete Neanderthal genome by year’s end.

Image: Wikimedia Commons/Thomas Ihle

  • Kemo D.

    Keep up the great work!

  • Jojo

    I don’t know. Sometimes I see people who have very small foreheads where the difference between their eyebrows and their hairline is relatively small compared to most people. Many have heavy eyebrow bones also. They look sort of like they might have some Neanderthal genes in them.

  • Felix Rocha Martinez

    They could not interbreed, they were hermaphrodites. Read my blog for more information, You may communicate with me at

  • The Sanity Inspector

    It’s just flabbergastingly amazing, the things we can learn with gene sequencing nowadays. Maybe in a few more years we can bring the Neandertals back, scientifically. As for their appearance, hey! Give him a flannel shirt and an black Gibson guitar, and presto it’s Neil Young!

  • Curious

    If interbreeding did occur, wouldn’t be possible to see the evidence reflected in differences in the the DNA of modern humans — i.e., between those descended from Neanderthal and those that were not? If this evidence cannot be demonstrated, why not?

  • C. Smith

    ?The team analysed (sic) the DNA of 13 genes from the Neanderthal mitochondria??

    What about the other 35000 genes?

  • troubled brotha

    I kinda resemble a neanderthal. To begin im half slavic, half black. My slavic father has all the same “abnormalities” as i do, but exaggerated. I got a real prominent, protruding and low brow ridge (unibrow too), a sloped forehead with a big lump in the back (my forehead/head loosk just like the picture above), as much hair on my upper arms as on my lower arms (check real quick – this aint normal), and I’ve never been able to throw as well as my peers even tho ive been just as interested in sports as them. My facial hair connects to my eyebrows (thinly but surely if you look close) , and my back is naturally slightly hunched. My arm span is 5 or 6 inches longer than my height. My feet turn outwards and my thighs slightly inwards, so my knees bend awkwardly.

    Are any of these PROVEN neanderthal traits? Or did i just get unlucky?

  • interesting subject

    England UK. My (male) arms seem unusually very strong in the ski-ing type of movement. (I also have (seemingly relatedly) strong shoulders. & fairly hirsute upper body). Perhaps bipedalism alone may not offer sufficient explanations? Could Skis or similar have been invented & used amongst earlier humans? Possibly a neanderthal trait? Earlier humans intelligence translated not only into tools, but also into assisted locomotion? Across ice/ski-ing? Over long periods of time? Sufficient for a physical trait like that to develop? My guess is we may all currently be one human species, but I’m also unsure how all human lineages/dna could be traced back for sure to exclude potentially varying ancestries.

  • Paul

    3 times the difference between neanderthal and different humans…, over 30 thousand years since neanderthals died out. I would think that even if there was limited interbreeding that there might be some rare individuals that would have some neanderthal dna in such a case. If there was limited interbreeding 30 to 40 thousand years ago the dna might not be across the board in our modern human genetics, but still might be in some human dna. Just something to consider.

  • L. H.

    interbreeding between species of divergent dna would likely result in sterility. e.g. horse + donkey = sterile mule Tiger + lion = sterile Liger et al…

  • thinkoutsidethebox

    It’s obvious through other studies among human populations (take Tasmania, for example) that Neanderthals and anatomically modern humans (what we call “us”), because of their lack of geographic isolation, most likely would not have been isolated enough to become to completely separate species. To create a mule, species must be isolated for about 2 million years, making Neanderthals less distinct than most would hope for. What differences we account for between Neanderthals and amh is probably regional differences and cold adaptation. I don’t think we know enough about DNA to even make these assumptions. Also, I think there’s a direct bias to Neanderthals (read the title! my gosh!) because people want to feel superior and “different” from people that no longer live today, even if they were our ancestors. We want Neanderthals to be stupid cavemen, not potentially comparable beings.

  • Bill Powell

    Perhaps when humans bread with neandrathals they produced a hybred like a mule that could not reproduce. These human mules left no offspring.

  • Antonio Torcoli

    the results do not completly rule out the interbreding: only the complete decoding of the dna contained in the nucleus will allow to exclude that modern humans have Neandertal ‘s genes.After all, the Mungo man is anatomically a sapiens like us but his mitocondrial dna is very different ; that simply means that working just with mitocondrial dna das not bring compelling evidences of anything

  • raffaele

    I thought about that possibility of some interbreeding between Neaderthal and Homosapiens over those thousand’s of years of co-existance and the probabilities would be high enough for it to occur.
    However the probability of an off spring from 2 different DNA structures would be very unlikely. If the DNA’s were close enough the offspring would be a hybrid and unable to propagate. So I concure with the results of the research. More then likely Homosapiens out thought the Neaderthals food supplies and led to an inevitable extinction. If one were to survive today we’d have as much in common with it as a Chimp in my opinion.
    A hypothetical question would be, could the same be true if say we found another civilization somewhere in deep space. Would interbreeding be a possibility ? Some food for thought.

  • NeoThal

    Well if humans did not bread with Neanderthals then we still don’t know where Rugby players came from?

  • den meyer

    This stuff fascinates me. If interbreeding occurred it would have to show somewhere in modern day humans. Are we looking

  • Lewis Bates

    Neanderthal diet was 85% meat. Therefore much competition from Cro Magon man who also ate meat but not as much. We exterminated them because they took most of the available game. Old Norse tales of trolls may be a race memory of Neanderthals .

  • db

    The conclusion is false.
    It appears to show that human males did not breed with Neanderthal females.
    It does not eliminate the possibility of Neanderthal males breeding with human females.
    In any event, over many generations it is quite possible that the mitochondria from neanderthal females could be replaced by that of human females by sheer volume of numbers and probability.
    For example, any new baby girl can inherit her mitochondria from either one of her two grandmothers.
    Thus, any putative female hybrid has a 50% chance of losing her Neanderthal mitochondria every single time her offspring mate with pure humans.
    So… this is bad science with terrible conclusions from the data.

  • Thought

    Also, the low level of testing on genes of 13 out of 35000 does not prove much. If there was a 2% interbreeding and most traits we selected out then there might only be a few differences and that might be lost in the error term we have within the population.

    People should also realise (And I’m not a scientist) that the ice ages came and went I believe every 25000 years… so there would have been constant flows out of Africa and Asia.

  • Jumblepudding

    It seems obvious that somebody should single out living people with the most neanderthal-like traits and sample DNA from that group. Neanderthal reconstructions often so closely resemble living people, that some uneducated fail to see the difference between us and them at all and wonder what the fuss is all about.

  • Rapido

    The results of this investigation actually shows that Neaderthals are more monkey then human. It proves for me again that Neaderthals are just a extinct monkey type, not human related at all.

  • Martha

    Neandertals wore armor and battled homo sapiens. Like many brutes in war, they took booty, which would include women. They began to prefer the more refined features of women to their own females, taking as many as they could. Unable to reproduce beyond one generation, like mules, they may have unwittingly designed their own quick demise.

  • Johnny Peace

    I WISH we had some evidence of Neandertals wearing ARMOR and battling anybody! Wow, what a spectacle!

  • http://Discovermagizine rj

    To db; females only get mitochondrial DNA from their mothers, not their fathers, therefore it is only through the female line or ONLY the mother’s mother that the mitochondrial DNA was passed. Not both grandmothers.

  • Batboysmother

    Well, of course they interbred! They were men, were they not? It may have been that differences between species produced problematic results in offspring, similar to the results of breeding a donkey with a horse…Mules can’t make more mules. Also, a modern human woman may not have been able to give birth to a hybrid child simply due to head size. These two senarios seem a common sense explaination for the absence of Neandertal hybrids in DNA.
    I suspect they were simply “absorbed”…in fact, I’m pretty sure my ex-boyfriend…



  • Roberta M. Soyars

    This article (“Global Warming May Have Helped Make the Incas Mighty”) helps to confirm what I have been preaching (to mostly deaf ears) for the past two decades:

    Roberta’s Law:

    “The only thing in the last 12,000 years, that could have been worse for Planet Earth than ‘global warming’, would have been lack of global warming!”

    How could the “human origins” guys have missed what really happened to the Neanderthals? They simply froze and starved to death, what could they eat besides each other?

    It’s a miracle that so-called “modern man” survived!

    Sure, I’m all for a clean, poison-free environment. The real problem is pollution, that’s a separate, but allied issue.

    Roberta M. Soyars

  • Thomas G. Hommes

    Our Eve’s apparently do differ very much – perhaps not enough for interbreeding. I am curious about our Adam’s. Since mules are not completely sterile there can be some Neanderthal DNA in white people.

  • James Ayers

    Modern examples of interbreeding suggest that it is commonly a one gender phenomenon. For example, when Europeans settled North America it wasn’t uncommon for European males to take Native American females as mates. The converse situation probably occurred but was more rare. Similar examples can be cited from all around the globe. Looking at ancient cultures, when Neolithic agriculturalists expanded out of the Middle East into Europe there is evidence that overtime females of the native paleolithic people were the preferred mates. Likewise, there may have been a preference such as Neanderthal males seeking amh females but amh males having little interest in Neanderthal females. Such a preference would not be shown by this study. Also, the Neanderthal species was very old. There were likely many mtDNA haplogroups. However there are very few Neanderthal remains to study. There is no way to rule out the possibility that one or more modern European haplogroups are Neanderthal in origin. There simply are not enough Neanderthal remains to test.

  • Interesting subject

    1. Is it possible that potential variations amongst earlier human-related beings might also have been influenced by gradual and perhaps indefinite or messy speciation processes amongst them?
    (As a quick example; ealier beings lived in very challenging, changing and diverse environments. A particular speciation process started with a very small number of individuals, but didn’t quite complete. They perished rather quickly and died out without trace, but not before leaving some of their genetic material, in what was possibly a messy lineage (eg. others had dispersed so never acquired the new material, or acquired only a diluted fraction of it)).

    2. Is it feasible that some of the earlier lineages (such as Homo Erectus/Heidelbergensis/other?) might have comprised de-facto intermediary forms, that other variants could reproduce with, so in effect reproducing with each other (even if they couldn’t do so directly)?

    To me it does seem the amount of variation may have been considerably greater in earlier times than presently.

  • Interesting subject

    Even if the above are not true, it seems the amount of variation may potentially have been considerably greater in earlier times than is presently known about. Also, inherent potential for variation may have been more significant amongst some species (perhaps including by implication sapiens, as it has survived a long time; perhaps also neanderthals ?).

  • Jeff Guarino

    You guys are wrong about interbreeding producing sterile offspring. If the species are close then the males are usually sterile but the females are fertile. Thus the mt dna is carried on through the female and the male y chromosome is wiped out. This would go perfectly with male neanderhtals taking african women. This would leave no trace of the neanderthal mt dna and also no trace of the neanderthal Y chromosome.

    There is plently on the internet about hybrids being fertile and carrying on. This is what happened when the europeans came to america. All of the early mixed people had native mtdna. (there was european Y chromosomes passed on because the male offspring were fertile).

  • Snuffles

    It is a rare event but there have been a few instances where female mules have given birth.

  • acadian

    re Jeff Guarino: Native Americans and European Americans are not different species (as horses and donkeys are). However Homo Neandertalensis and Homo Sapiens are different species.

  • Kokapelye

    What this study conclusively proves is that one Neandertal mtDNA lineage has no modern descendants. It shouldn’t be surprising that ancient lineages go extinct. In the case of mtDNA, all that is required is the bad luck not to have any female offspring and that’s the end of the line, literally.

    Scenarios can be postulated that would decrease the survival of female descendants to carry on a mtDNA lineage. For example, modern human groups have practiced female infanticide, so it’s not unreasonable that groups of Neandertals—or even their amh descendants—may have practiced female infanticide. Possible incompatibility of the shape of a “hybrid” fetus’ head with the Neandertal birth canal may have increased mortality in childbirth for Neandertal mothers and their “hybrid” offspring, and greatly diminished the likelihood of Neandertal mtDNA finding its way into surviving lineages.

    Finally, species designations are hypotheses about how we think organisms are related. Species designations follow what is understood about these relationships rather that performatively create these relationships. Homo neanderthalensis and Homo sapiens indicate that we think these groups are separate species. Calling them that does not necessarily reproductively isolate them any more than designating them Homo sapiens neanderthalensis and Homo sapiens sapiens makes them reproductively compatible.


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