The caveman inside: The first full draft of the Neanderthal genome suggests that modern humans and Neanderthals (a skull of which is shown here) interbred.
Jim MacKenzie/UCSC
Genetic evidence suggests there's a little Neanderthal in all of us.
Last year, an international team of researchers announced that they had completed the first draft of the Neanderthal genome--more than three billion nucleotides, sequenced from three minute samples of bone powder. Now, in two papers published today in Science, the group reveals in-depth analyses of the data and provides an unparalleled glimpse at human evolution. By comparing Neanderthal DNA with that of living humans from around the world, the scientists have found evidence that--sometime between 50,000 and 80,000 years ago--modern humans and Neanderthals interbred.
Archeologists' traditional view of human evolution, gleaned from carbon dating, skeletal structure, fossil location, and, more recently, Neanderthal mitochondrial DNA, posits that humans today are descended from a small group of individuals that migrated out of Africa and dispersed throughout the world. But the new research shows that modern humans in Africa have a lower percentage of the Neanderthal genome than non-Africans do--implying that the founder group that left Africa interbred with Neanderthals before moving on to populate the other continents. "Likely, it took place somewhere in the Middle East or in northern Africa, perhaps at the gateway as they were migrating out for the first time," says Harvard University geneticist David Reich, who performed the population genetics analyses.
The scientists used just half a gram of bone powder, collected from the bones of three individual Neanderthals excavated from the Vindija Cave in Croatia. The data they provide tells a story not just of migration but physical evolution, and allows researchers to isolate what makes humans unique. "The Neanderthals are our closest evolutionary relative," says Svante Pääbo, the project's leader and director of genetics at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. He notes that now scientists can begin to ask what genetically differentiates us from our closest living relative--the chimpanzee--and our closest extinct one.
So far, the answer to this question appears to be "not much." According to the researchers, humans inherited anywhere from 1 to 4 percent of their genomes from Neanderthals; not only does the amount vary among individuals, but the actual location varies, too. "There's no indication at this point that there was any particular gene with selective advantage that came in from Neanderthals," says Richard E. Green, a biomolecular engineer at the University of California at Santa Cruz who was responsible for much of the genetic sequencing. "The signal appears to be widely distributed across the genome, and differs from individual to individual."
Scientists announce the first complete draft of our closest relative's genome.
A new generation of DNA-sequencing machines is opening up whole new areas of genomic research. Already, researchers are unraveling how modern humans differ from Neanderthals and devising more precise tests for cancer.
I think they mean 1% to 4% of our modern genome comes directly from Neanderthals. Not that we only share that much in total.
And you are correct. If they can breed then technically they are the same species. However, species categorization started long before breeding ability was taken into account. So tradition has us say "species" when really it is a sub-species.
trans,
You are correct: 1% to 4% of our modern genome comes directly from Neanderthals. That sentence has been amended.
Yes, I wrote that incorrectly. Humans definitely share far more than 4% of their genome with Neanderthals. The story should actually read: According to the researchers, anywhere from 1 to 4 percent of the human genome has been inherited from Neanderthals.
Sorry about that!
Thank you. I am still at a loss to explain the findings. One would think that if humans interbred with Neanderthals, they would also have inherited genes from the humans. How do we know that the 1-4 percents we have in common with them did not come from us in the first place? Just thinking out loud.
The study found that Europeans had more Neanderthal genes than Africans, implying that the mixing of genes occurred after the "out of Africa" migration of humans. Presumably genes in all humans and all Neanderthals are a from common ancestor, other genes in all humans or else in all Neanderthals are species specific. (Of course the test is skewed because only 1 Neanderthal was sequenced.)
Neanderthal are a sub-species of homo sapiens, some modern Europeans, share physiological features with Neanderthal, i.e. mandibular foramen. (lower jaw nerve canal)
Er, beyond the scientific evidence, being Caucasian myself I feel safe in saying this, there are some individuals in our race that seem to coincidently share gross anatomical similarities with Neanderthal.
If it were not for a resistance of some faiths, creeds, and beliefs among Caucasians- this would have seemed to be the more logical explanation given the differences between Caucasians and the rest of the world. Caucasians interbred with Neanderthal to a higher degree than other homo sapiens in other regions and retain features like facial hair, white skin, and eye color variation.
What interests me is the resistance to this assumption. It is illogical to assume that inbreeding alone created these general Caucasian characteristics. Interbreeding is a much easier answer.
Great study! Thank you for this significant contribution.
Sorry to break it to you, but if I read the paper correctly, it sounds like Homo neanderthalensis had _dark_ skin. Here's the relevant quote from the paper:
-------
We identified no fixed start codon differences, although the start codon in the gene TRPM1 that is present in Neandertals and chimpanzees has been lost in some present-day humans. TRPM1 encodes melastatin, an ion channel important for maintaining melanocyte pigmentation in the skin. It is intriguing that skin-expressed genes comprise three out of six genes that either carry multiple fixed substitutions changing amino acids or in which a start or stop codon has been lost or gained. This suggests that selection on skin morphology and physiology may have changed on the hominin lineage.
These genes regulate melanaphores, we all have melanophores. Here is another link you might find interesting - http://tinyurl.com/Red-Haired-Neanderthal - If Homo Sapiens came out of Africa it would be likely that these individuals were dark skinned. I hope this is not offensive to you.
The alternate hypothesis you might be proposing is that Homo Sapiens interbred with Neanderthals, inherited 1-4% of our genome from them, (European lineages) but do not have any grossly observable inheritable characteristics. I.E.The appearance of Caucasians is not in any way related to this genetic heritage.
That is illogical IMO.
Hi
Would it be possible to link these genes to the human genome project or some similar project?
What characteristics would manifest in individuals with a high percentage?
Regards
Element
So this basically prove that multiregional hypothesis is correct, right?
Neanderthal study needs more work (earthworm study says we're linked too)
Hi,
Interesting story, but I think it needs more work.
There was a similar study that stated DNA of earthworms and humans had a lot in common.. the problem is that a small % difference can be a huge difference.
I don't want to wait until I'm an old man a read a story that this Rewrite of Human Evolution was a mistake... but then again it's happened before in scientific history.
By the way, who is funding this research?
Genetic analysis of modern DNA
I remember the wrangling over the out of Africa hypothesis and the regional hypothesis in the 90's. Many anatomists claimed that regional variations in todays humans were correlated with traits from other humans that had lived in the same regions. This, they argued, supports the idea that there was interbreeding.
As it was presented in the science media in the 90's geneticists came in and convincingly showed there was no significant interbreeding. I think this was based on statistical analysis of mitochondrial DNA and y chromosomes of modern humans. A lot was based on this statistical analysis. They argued that the anatomical evidence was fuzzy, non- quantifiable evidence--not rigorous like the statistical analysis. My impression was that they claimed the regional hypothesis was just inconsistent with the data.
Well, it looks like somebody either did earlier genetic analysis wrong or allowed statements that exaggerated the certainty of the result.
Does anyone know anything about the reported confidence of earlier claims that genetic data supported only the out of Africa hypothesis? Or did I just misunderstand what was said at the time?
What the heck is a 3-minute sample? Does that mean that it cooks for 3 minutes or only lasts for 3 minutes? Or do you mean that 3 minute (as in very small) samples were used?
suggestive, but can't jump to conclusions.
The shared dna, could have been tranferred to human via a virsus. Just a thought.
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357 Comments
Something Strange in the Air
How can humans share only 1 to 4 percent of their genome with Neanderthals while sharing more than 90 percent with chimpanzees? That does not compute. Are we not taught that homo sapiens, chimps and Neanderthals all evolved from the same ancient apes? If homo sapiens could breed with Neanderthals, one would think that the difference between humans and Neanderthals would be a lot less than the difference between humans and apes. After all, humans cannot breed with apes.
On a second tangent, why is a Neanderthal considered a different species of hominids (due mostly to the morphological differences) while different races of modern humans are considered to be a single species? After all, there can be huge differences between the races.
Just asking. Inquiring minds and all that.
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