Svante Paabo believes modern humans & Neandertals interbred

Neanderthals 'had sex' with modern man:

Professor Svante Paabo, director of genetics at the renowned Max Planck Institute for Evolutionary Anthropology in Leipzig, will shortly publish his analysis of the entire Neanderthal genome, using DNA retrieved from fossils. He aims to compare it with the genomes of modern humans and chimpanzees to work out the ancestry of all three species.
Paabo recently told a conference at the Cold Spring Harbor Laboratory near New York that he was now sure the two species had had sex - but a question remained about how "productive" it had been.

"What I'm really interested in is, did we have children back then and did those children contribute to our variation today?" he said. "I'm sure that they had sex, but did it give offspring that contributed to us? We will be able to answer quite rigorously with the new [Neanderthal genome] sequence."

The way Paabo is couching it, what he has found then seems likely to be evidence that humans who had just expanded Out of Africa contributed to the genomes of Neandertals. In other words, modern human introgression into Neandertals. Of course if the gene flow was from modern human to Neandertals exclusively, then it would be an evolutionary dead end since that lineage went extinct.

In any case, for several decades some fossil-based paleoanthropologists have been claiming that there are "intermediate" individuals in the record which indicate modern human-Neandertal hybridization. Most prominently Erik Trinkaus. If Paabo's finding becomes more solid, then it seems time to update the probabilities on these sorts of claims based purely on morphology.


Related: Neandertal introgression.

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but.... every case of fossil based hybrid has been retracted, as far as I know. Early H. sap and contemporary N's were just too similar to draw conclusions ...

What I would like to know more about (and this is coming) is the relationship (degree thereof) between European H. sap and living humans.

Since the discoveries of Levallois technology tools in the U.S. recently, the migration theory and where neanderthals were all located is now in question,. Indiana,Texas, and Tenn. have all been yielding Mousterian style tools for the last six years. An entire lithic industry never seen before in the U.S. has been revealed. Every type of tool found on neanderthal sites abroad have been found in the U.S. Only to be ignored so far by main stream archaeology because it has been revealed to amatures. But the artifacts themselves speak to the truth of it. They are undeniably a prepared core design that until now has only been seen in lower and middle paleo sites abroad. It would serve Paabo, Trinkhaus,and the others well to take a close look at the recently assembled artifacts. These recent finds change everything as far as dispersals and migrations of at least the middle paleo cultures...rick doninger

By rick doninger (not verified) on 26 Oct 2009 #permalink

I find it hard to believe that modern man didn't have sex with Neandertals -- after all, we will jump anything -- but whether it produced hybrids is a completely different question.

The genetic evidence so far hasn't shown any evidence for hybrids, but maybe the full sequence with. I haven't hard anything in that direction so far, though, and when I visited Paabo's group last month they didn't say anything about it, so if they have found it at least they are not revealing it to outsiders like me :)

I really look forward to reading the genome paper. Svante promised to send the draft when they have it, so I am waiting impatiently.

Of course, we are talking very low coverage sequence here, so even if the new sequence doesn't show any evidence for hybrids it doesn't conclusively rule out that we have left over Neandertal DNA in our genome. When we get deeper coverage over the next couple of years we should have a much better idea of it.

Comparing our modern genome with the Neandertal genome will of course only tell us if any Neandertal DNA entered our gene pool and survived till modern day. Getting a sequence from Homo sapience from ~30000-50000 years ago would be better, and it is possible to get that, even if contamination issues are harder to deal with for that than it is for Neandertals (and there it is hard enough as it is).

BTW, about a year ago my impression from Svante was that there was no gene flow seen in the record. His belief at that time was that there was no gene flow but of course they had sex because, well, they would. So whatever new report of evidence of gene flow follows a moment when it seemed that there was no positive evidence of such.

greg, yes. he was unequivocal about it. the about-face means

1) there must be something compelling or

2) british newspapers are making stuff up again

"The genetic evidence so far hasn't shown any evidence for hybrids"

Apparently Neanderthals had the human version of FOXP2, yet the genomic estimates in humans are that the gene is something like 40,000 years old. Hard to come up with a scenario other than it having come from Neanderthals. Similarly for the 7R version of the D4 dopamine receptor.

Henry Harpending

By Henry Harpending (not verified) on 27 Oct 2009 #permalink

Henry, are you sure about FOXP2?
It was my impression that it was a different gene, that for the variant of microcephalin, MCPH1, that is believed to be 42,000 years old and that this was NOT found in the neanderthal sequence.
The way I read the story is that there is a possiblity that neanderthal sequence reveals something that would have made hybridization with humans difficult - for instance a chromosomal difference (inversion, translocation etc). This would have greatly limited the chances of having fertile pairings between neanderthals and modern humans.

"Similarly for the 7R version of the D4 dopamine receptor."

Really?! Hadn't heard this. Very interesting.

A little google-foo lead me to this study:

From the study:

"we show by DNA resequencing/haplotyping of 600 DRD4 alleles, representing a worldwide population sample, that the origin of 2Râ6R alleles can be explained by simple one-step recombination/mutation events. In contrast, the 7R allele is not simply related to the other common alleles, differing by greater than six recombinations/mutations."

--This, obviously, makes 7R old. But the article goes on:

"Strong linkage disequilibrium was found between the 7R allele and surrounding DRD4 polymorphisms, suggesting that this allele is at least 5â10-fold âyoungerâ than the common 4R allele."

--Yep, this makes it young, at least in humans. So what this is implies is that this is a very old allele that did most of its aging in a population not represented as a subset of modern humans.

Sigmund said "Henry, are you sure about FOXP2?"

MCPH too, but also foxp2. See

The Timing of Selection at the Human FOXP2 Gene
Graham Coop*, Kevin Bullaughey{dagger}, Francesca Luca* and Molly Przeworski*
MBE 2008 25:1257-1259


By Henry Harpending (not verified) on 28 Oct 2009 #permalink