This news just appeared. The conventional wisdom for the last decade has been that Neanderthals died out without leaving any descendants. That is, their genes died with them. Although Neanderthals were contemporaries of H. sapiens, and might have mated with them, they either didn’t hybridize or their “hybrids” were sterile.
Now, a new study by Svante Pääbo and his colleagues confirms that this genetic “introgression” did indeed take place, and that between 1% and 4% of the DNA of Europeans, Asians, and Papua New Guineans is attributable to hybridization between “modern” humans and Neanderthals. The paper will appear in Science tomorrow, and is not yet online, so I haven’t seen it. There are reports at the Guardian and the BBC, and the figure from the BBC website is below.
Oh, and Carl Zimmer, who’s undoubtedly seen the paper, has more.
Fig. 1. Introgression! Neanderthals copulate with Homo sapiens!
As one of my colleagues, who will remain unnamed, wrote me: “Now here’s a piece of speculation – what will happen when they get round to the floresiensis genome? I presume someone is beavering away at it. If we f****d Mr. or Ms. Chunky, surely we had a shag with the leprechauns!”
Update: The paper is now online here. Look at all the authors! And although I mentioned Pääbo above, the first author is Richard Green.
h/t: Greg Mayer and Matthew Cobb for the alert.
Amazing and fascinating!
I am sure Dr. Dino is going to have a field day with this from behind his prison bars 🙂
Way to go!
I’m not sure why, but this makes me smile.
Excuse my naivete on the subject, but does the 1-4% figure (of modern genes due to hybridization) imply that 96-99% of modern genes are solely from ancient Homo sapiens? How are the shared genes from sapiens and neanderthalensis accounted for in the estimate? After all, the two species have a not-too distant common ancestor.
I’m no biologist, but the paper seem to measures gene difference in the simplest way, looking at SNPs of alleles. They used “biallelic SNPs” with two humans having different alleles and one Neanderthal having the derived allele, which seems to be a suitable way to enhance signal against random changes.
“We measured the difference in the percent matching by a statistic D(H1, H2, Neandertal, chimpanzee) (SOM Text 15) that does not differ significantly from zero when the derived alleles in the Neandertal match alleles in the two humans equally often. […] We find that the Neandertals are equally close to Europeans and East Asians: D(ASN,CEU,Neandertal, chimpanzee) = –0.53 +/- 0.46% (11 SD from 0% or P << 10−12) (table S51)." [p 718.]
The 1-4 % number is derived by looking at the ratios of a derived ("unnormalized") variant of that statistic (see p 721), which gives the proportion of Neanderthal ancestry of non-Africans. This means AFAIU that 96-99 % of alleles are phylogenetically a clade for the humans, while 1-4 % show mixing between humans and Neanderthals.
Carl Zimmer wrote a very good article.
I thought that was obvious. They run religions and do their best to curtail intelligent thought since they envy their homo sapiens cousins.
The papers by Green et al. (http://www.sciencemag.org/cgi/content/full/328/5979/710) and Burbano et al. (http://www.sciencemag.org/cgi/content/full/328/5979/723) are now online with open access.
Apologies for the following, but I couldn’t resist…
Is it on your grandfather’s or grandmother’s side that you claim descent from the neanderthals?
Well, don’t you think you could decide that for yourself?
[The paper claims it’s equally likely on both sides, so that’s what I’m going for.]
LOL, I think NoA was paraphrasing a question posed to the biologist Huxley about his belief on humans evolving from primitive species.
Neanderthals, eh?
That explains why I like Adam Sandler films.
Ah, eagerly awaited and more data and results than expected! (Carl Zimmer’s article is a tour de force walk through on the subject, btw.)
Finally the expected introgression, but surprisingly low. I gather that one explanation can be that the initial event was small and early but the H. sapiens population expanded fast to blow up the gene proportion, while eventual later events as in space and time shared parts of Europe happened when the population was already large and swamped the gene flow. In that case were is no need for other causes to intrude. (Say, a specific taboo against mixing.)
Noting the 1-4% range, will we now have an assay for predisposition to listening to Rush Limbaugh & Ann Coulter?
Oh great..now my friends have even more fodder to make “neanderthal” jokes at my expense. 🙂
We can haz Neaderz.
Carl Zimmer says it doesn’t actually necessarily mean that we interbred successfully with Neanderthals. This is a bit dissappointing.
No he just pointed out that there are a few competing hypothesis that have not been ruled out. That is different from saying it did not happen, and that the evidence suggests it might have
And that it is the simplest explanation as well. The others IIRC involves multiple gene flows and/or timely segregation (if that is the term) over a longish period.
I remember Jerry saying that he thought a particular drawing of him looked a bit too Neanderthal… –maybe the artist captured a hidden truth?
If Neanderthals died out 30,000 years ago, that would be about 1500 generations. Say one Neanderthal interbred and passed on 1/2 of their genes. After 1500 generations, there would be a 1/(2^1500) chance that any of those genes remain. There is almost certainly no Neanderthal genes (or alleles) remaining in any genome.
You are under the assumption that all changes are random and that all genes can be changed equally over time. Not true.
You are so full of shit. It doesn’t work like it appears you think it works. Once the DNA gets in, it could stay for the remaining life of the species. In fact, the very basics of life from approximately 3.5 billion year ago are still in our genes.
That is exactly what the paper says _isn’t_ observed.
One explanation explored is that the Neanderthal alleles have participated in selective sweeps. Your assumption of randomness is, as NEB notes, not relevant in general and here explicitly falsified.
But as IIRC Hawks notes, the Neanderthal genes haven’t been successful as such or we would have noted (more and/or easier seen) Neanderthal traits. It just happens that selection is strong in this one species, because of a large population.
Btw, these alleles seems to have survived 60 000 years, not 30 000.
Jerry… Those matings were accidents.
No, they just wanted help with their luggage.
ROFLMAO
This of course doesn’t mean we weren’t the direct cause for why they died out, archaeological evidence shows we ate Neanderthal flesh, and genetic evidence also shows we were habitual cannibals. I’m wondering whether Australian Aborigines have any Neanderthal links?
***Noting the 1-4% range, will we now have an assay for predisposition to listening to Rush Limbaugh & Ann Coulter?***
Ironically, although they are seen as backward, the neanderthals may have contributed some useful genes for cognition. Bruce Lahn noted one a few years ago:
“”The gene microcephalin (MCPH1) regulates brain size during development and has experienced positive selection in the lineage leading to Homo sapiens,” the researchers wrote.
By no means do these findings constitute definitive proof that a Neanderthal was the source of the original copy of the D allele. However, our evidence shows that it is one of the best candidates,” Lahn said.
“The D alleles may not even change brain size; they may only make the brain a bit more efficient if it indeed affects brain function,” Lahn said.”
http://www.msnbc.msn.com/id/15611031/
Very interesting. The first and oldest skeletons of humans found in Australia were ‘robust’ a bit like Neanderthals and it is thought that humans reached Australia perhaps 60,000 years ago. The robust type seems to have died out and were replaced by the more ‘gracile’ or African type. The mitochondrial DNA of todays Australian Aborigionees derives from M and can be clearly traced from Africa through the Arabian peninsula, India and on through S E Asia to Australia. Perhaps the earlier ‘robust’ arrivals in Australia had a higher Neanderthal gene content but were swamped by the new gracile arrivals. If this is the case than perhaps it may be found that present day Australian Aboriganees are at the 4% range. It will be interesting to see if that is the case.
Why don’t Neanderthal Y-Chromosome and Mitochondrial DNA haplotypes show up in humans today? The only way this could happen is for Neanderthal women to have had only male descendants or Neanderthal men to have have had only female descendants. This is a bit unlikely. All known Y-Chromosome and Mitrocondrial DNA haplotypes outside Africa are traceable back to the original migration by modern humans out of Africa. Why is this not explained in the article?
You are wondering about Battlestar Galactica … I think…
I think may be true that we could have some gene from the Neanderthal species. Sapiens and Neanderthal are quite similar, so we can bring something from our “friends”.
Well… if you see my blog, you can notice just from the title what i mean ^^