E-mail updates
Follow on Twitter
Subscribe to RSS
M. Hofreiter / K. Fiusterweier
Researchers say some Neanderthals may have had pale skin and red hair similar to that of some modern humans. Explaining the genetic similarities, however, can lead to a tangled tale.
One of the most titillating tales in the study of human origins — focusing on whether Neanderthals interbred with modern humans — has just gotten more tangled.
Over the past couple of years, studies of Neanderthal DNA samples painstakingly extracted from ancient bones have suggested that contemporary non-Africans can trace up to 4 percent of their genetic code to our long-extinct Neanderthal cousins. The genomes of modern-day Africans, in contrast, have virtually nothing in common with the Neanderthals. Researchers assumed that the genetic contribution for the non-Africans was passed down through cross-species sex during the time that Neanderthals and Homo sapiens lived in close proximity in Europe, tens of thousands of years ago.
However, there's another possibility: Maybe that common genetic code was passed down from the common ancestor of Homo sapiens and Homo neanderthalensis, hundreds of thousands of years ago in Africa. Today, researchers at the University of Cambridge reported in the Proceedings of the National Academy of Sciences that such a scenario provides a better fit for the genetic data. They say there's no need to assume that anatomically modern humans did the Neanderthal nasty, a process known more scientifically as hybridization.
"Our work shows clearly that the patterns currently seen in the Neanderthal genome are not exceptional, and are in line with our expectations of what we would see without hybridization," the lead researcher, Andrea Manica, said in a Cambridge news release. "So, if any hybridization happened — it's difficult to conclusively prove it never happened — then it would have been minimal and much less than what people are claiming now."
Modeling population dynamics
Manica and his colleagues set up a computer model for the last half-million years of population dynamics, with the assumption that there were two migrations from Africa. The first migration led to the settlement of Europe by the ancestors of the Neanderthals, hundreds of thousands of years ago. Then, around 300,000 to 350,000 years ago, the route from north Africa to Europe was cut off somehow. The European and north African populations showed gradual genetic divergence, but still retained a bit of common heritage from their mutual ancestors.
When the second migration from Africa took place, around 60,000 to 70,000 years ago, the north Africans who dispersed to Europe and Asia would carry that extra bit of genetic similarity with them. But the Africans who lived farther south and stayed behind on the continent wouldn't have as much genetic kinship with the Europeans.
The researchers found that their model did a fine job of accounting for the existing data without Neanderthal sex.
So what do the researchers behind the earlier DNA studies say? That's where it gets really interesting: One study, published online in April in Molecular Biology and Evolution, contends that ancient population dynamics alone can't account for the genetic patterns seen in the DNA from Neanderthals and modern humans. Another study, posted on the arXiv preprint server and due for publication in PLOS Genetics, takes a closer look at a genetic pattern known as linkage disequilibrium — and concludes that modern humans and Neanderthals interbred somewhere between 37,000 and 86,000 years ago. Nature's Ewen Callaway delves into the details surrounding those claims and counterclaims.
Either-or proposition?
So, to recap: Some scientists say the population dynamics that were in effect hundreds of thousands of years ago can explain genetic similarities between populations, even if those populations never interbred. Others say the evidence is getting stronger that modern humans and Neanderthals really did mate when they met up in Europe, tens of thousands of years ago.
University of Washington geneticist Joshua Akey says both sides just might be right.
"To me, I don't think it's a case of either-or," he told me. "I think that both things can be going on."
Akey and other researchers recently published a study in the journal Cell suggesting that a mysterious "Neanderthal sibling species" made a genetic contribution to the DNA of modern-day Africans. He said that interpreting whether genetic similarities come from a common ancestor (a process known as archaic population structure) or from more recent cross-species sex (a process that Akey calls introgression) is a tricky but essential task for those who study human origins.
"Ultimately, it's important that we come to a consensus as to one process or the other, but I find them both to be interesting interpretations," Akey said. "Introgression is a sexier mechanism, but even if it turns out to be a case of archaic population structure, that still tells us something about our past that we didn't know before."
So did modern humans do it with Neanderthals or not? And to what extent? Today, maybe it's a tangled tale, but that won't necessarily be the case forever. Akey said he was optimistic that researchers will be able to "tease apart" the different influences from the two processes within the next year or so.
Update for 2:10 a.m. ET Aug. 14: In a follow-up email, Akey clarified his view on the "did they do it" question, leaning toward the affirmative:
"Although I do think that both ancestral population structure and introgression are not mutually exclusive events, the recent papers from David Reich and Monty Slatkin show pretty compelling evidence that introgression of Neanderthal lineages into anatomically modern humans occurred. Thus, the real debate moving forward will be about the relative contributions of these two processes."
More about ancient hominid sex:
- Neanderthal-human sex rarely produced kids
- Ancestors had sex with mysterious human cousins
- How sex with Neanderthals made us stronger
Cambridge's Anders Eriksson is Manica's co-author on the paper published by the Proceedings of the National Academy of Sciences, titled "Effect of Ancient Population Structure on the Degree of Polymorphism Shared Between Modern Human Populations and Ancient Hominins."
Authors of the study in Molecular Biology and Evolution are Melinda Yang, Anna-Sapfo Malaspinas, Eric Durand and Montgomery Slatkin.
Authors of the preprint destined for PLOS Genetics are Sriram Sankararaman, Nick Patterson, Heng Li, Svante Pääbo and David Reich.
Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the dwarf planet and the search for new worlds.
Leave a Comment:
We might generate better answer if we change the question. After all, the question isn't whether we did it or not with Neanderthals -- we've been caught doing it with all sorts of biologically non-humanoids all across recorded history and that doesn't even delve into the deeper issue of our common ability to pretend that other clear humanoids (ie: any racial group other than us) are somehow less human than us and therefore fair game for such "dalliances." The question is whether such unions produced fertile offspring. And that seems more a question, to me at least, that a geneticist should answer than that which a historical statistician presents.
In this case they are one and the same, they are looking at the genome. The "historial" doesn't come into it, these are observation of modern genomes today(sometimes compared with fossil genomes).
D'oh, "historical". Well, that is the same too, since we are dealing with observations, not histories.
Dave, I've thought the same thing - hybrids are often infertile (mules), and if the neandertals, with dwindling populations, sought to boost their numbers by bringing modern humans into their group, they may have unwittingly hastened their extinction. Just a thought.
Sooooo... doing a neanderthal was the first form of birth control ?????
So which one was Adam in which one was Eve?
I'm more interested to know their favorite position....
The main barrier that divides one species from another is the number of chromosomes each posses. Thus if one species has 30 chromosomes and the other has 28, the egg and sperm of these animals would have 15 and 14 chromosomes respectively. Their offspring would have 29 chromosomes, an odd number that does not divide evenly producing defective eggs or sperm. That is why a mule or a tiger, lion offspring are sterile and can't produce baby mules or tiglons. I've followed this topic of Neanderthal and Human mating for many years and have never seen any information about Neanderthal chromosome count.
Yes wade-3708300, trying to mate with a species that has a different chromosome count than you can be considered safe sex.
Hybrids are indeed often infertile, but not always. The closer the match in DNA form (chromosomes) and function (genes), the better the chance that a hybrid will be fertile. By all accounts, Neanderthals were indeed very close to modern homo sapiens.
I agree. Humans will have sex with just about anything that moves, and some things that don't. So the question is one of viable offspring. That's going to be very hard to prove one way or the other.
Knowing humans, I have no doubt they had sex with Neanderthals.
According to my wife I am living proof that Neanderthals are alive and well!
Hard to imagine two groups of homo (sapien and neanderthal) coming into contact with each other and NOT having sex.
It's just not how we do things, lol.
this could be proof of when "BEER GOGGLES" where invented
One Cro-Mag to another: "Don't eat the fermented berries, I did yesterday and this morning I woke up next to a Neanderthal."
So you're telling us that your wife continues the tradition of doing it with Neanderthals.
The question of Modern Human and Neanderthal matings producing viable offspring is pretty much a settled matter if there are Neanderthal genes in modern living humans without viable offspring such genes would not exist. They do exist.
Show me a street mutt dog with the hip dysplasia that plagues so many highly bred championship breeder dogs, it pretty near doesn't happen because of a phenomenon called hybrid vigor. A broad genetic base give an individual a much better chance at genetic health. Incest is a serious wrong for a very good reason.
We are blessed to be the Mutt Apes.
Another thing to add to this is Neanderthal would have been a diverse group just like humans are today. If you look across Europe or other parts of the world you would see a great diversity of people from one region to another. Neanderthal did have a lot longer time to become diversified.
Some pockets of Neanderthal may have had the right genes to reproduce with humans but most did not. And as BearZZZ pointed out when Neanderthal died out some of their descendants still live on in us. Just like the Cuban Indians. If she is still alive there is only one left but most Cubans are descended from the Cuban Indians.
The only way to get a handle on this would be to catalog as many human DNA’s as possible. Then map backwards to Africa.
Of course they had sex, have you seen some of those hairy bastards on tv? The missing link has been found. P.S. The dude on the left, sorta looks like Carrot top.
To a human of the period a Neanderthal wasn't a distinct species as we clearly see it now, but perhaps a exotic, strange member of a different tribe. That would probably be as tantalizing to them as it members of different ethnic groups are to us. To me there is no doubt that they mated, and that the genetic evidence present today is evidence of such interbreeding, not of common ancestry.
Ancient peoples had the means, motive, and opportunity... DNA don't keep those dirty secrets. If it were possible for them to do it, what on Earth would stop them???
I did not have neanderthal sex with that woman . . .
Bill Clinton had sex with a Neanderthal at least once - Chelsea was born.
That is really disgusting and you probably think it's funny
Hummm.....
That would explain the drunken little bush.
The one in the mirror looks exactly like that Olympic snow boarder guy.
They are still having sex everyday, in Detroit.
Nice try bro, but your joke doesn't really work considering that modern Africans are distinct in apparently not having Neanderthal DNA.
Mario, I agree that they probably wouldn't have any conscious concept of being "different species," but they certainly would have understood "different," and sometimes that is enough. But yeah, someone is going to get frisky eventually.
I would think there is also the possibility of rape.
I thought that as well, hambone. Especially since rape is often an expression of dominance. If tribes were aggressive toward one another, you could bet money on this happening.
Dave, they were so closely related that I think most geneticists assume they would have fertile offspring, but of course that can't be proven, and an undisputed hybrid has still never been found.
The genome is hybridized, that is what they have found over and over.
Of course, but I was referring to an individual, F1 hybrid, which would help support the hypothesis that the common genes were from direct hybridization rather than common ancestry.
Isn't the Headline for this article incorrect?
Weren't Neanderthals "human"?
Shouldn't it be stated differently?
Something like -"Did human species interbreed?"
Generally, there's a distinction between "modern humans" or "anatomically modern humans" and Neanderthals. It's Homo sapiens vs. Homo neanderthalensis. The term is squishy, though, and I think I get your point. I suppose the best way to put it would be "Did hominin species interbreed?"
http://archaeology.about.com/od/hterms/g/hominin.htm
When you consider the difference between a chimpanzee and a human, and then consider the difference between Homo Sapiens and Neanderthals, the difference seems almost insignificant. If the union between Sapiens and Neanderthals could produce fertile offspring, then perhaps the two groups should be considered different races of the same species, rather than different species. (If you gave the guy in the mirror a modern haircut and a pair of jeans, he would probably go unnoticed on a city bus).
Yes and it sounds less like the blog of a spotty 15 year old boy living in his parent's basement, as well.
Except you're missing one thing. The average person probably wouldn't click on such a title, but a phrase such as "do it" connects with their mindset. However, someone with actual scientific interest in the subject will most likely click regardless of which title is chosen. So, by making the title sound like the blog of a 15 year old, you increase your readership and trick the average person into reading something about science instead of who was recently booted out of the Big Brother house.
tricked into reading science! lol. :)
fossafun you got injected by Boyle himself. Impressive.
A little boy comes to his dad and asked him, "Dad, where did we come from?", his father answered, "A long time ago, GOD created Adam, and He created a spouse for him, they procreated and we came from them". The boy goes away, content with this answer. Few days later, the boy came to his dad, and angrily says "Dad, you lied to me, you said that we came from Adam and his spouse, but mom told me that we came from apes, why did you lie to me dad?" The father said, "look son I was not lying, you see, I was talking about where my side of the family came from, and she was talking about where her side of the family came from.
I can't remember where I read this joke, but I think it is apropos.
Not really, because in that comparison we are still apes. It is just mirroring how little sense creationist ideas make.
"Oh, boys...look what I got here!"
"Hey, where all the homo sapien women at?"
You're not very intelligent, are you? I think we've found our modern day neanderthal folks.
Bob wins for a Blazing Saddles reference!!! Awesome!!!
Thanks, Hood, for proving yet again that Creationists deny reality based purely on their vainglorious ego.
The same sort of mentality that made the Church refuse to accept that we were, in fact, NOT the center of the universe. Imagine what sort of blow that was to their collective ego? Finding that out?
Now those same sort of intrepid scientists say we EVOLVED! Gasp, that must really be a humbling thought. Can't have that now, can we? Unfortunately, the Church can't imprison and burn scientists anymore for having the audacity of suggesting that we are not as super-special as we think we are.
Hey, you guys are being unfair to Creationists! They've made progress lately.
I've actually seen it argued that God only created white people, and the other races are in fact evolved from lesser apes!
LOL. So now God is a racist too. Wonderful.
Look, if you read the bible, it's pretty obvious that the people God created were the Jews. The other people Cain went to live with, Cain's wife included, were all the rest of us apes.
There are people out there that have sex with animals. What the hell makes them think that humans would not sex with neanderthals?
humans ARE animals silly
Hey...Isn't this a moot point ... although it is interesting? I am interested in what science shows, but do not pass any judgement on it...good or bad. I have know people in my life who I swear had nethanderal traits both physically, mentally and with their rough sexual desires. Any one else who has been there?
Connie, I get your point, but - who among us has actually witnessed neandertal sexual traits? They may have been the gentlest lovers in (pre)history. :-)
The fact that the genomes of modern day Africans have nothing in common with the Neanderthals, and other modern day humans have about 4% in common with the Neanderthal genome should indicate interbreeding. If the genes that modern man shares with the Neanderthals was merely the result of Homo Sapiens and Neanderthals having a common ancestor, then wouldn't ALL Homo Sapiens (modern Africans included) have that 4% in common with the Neanderthals?
There's something strange about the 4% part. We share 98% of our DNA with chimps; only 2% is different, and chimps are another species, nowhere near as close to us as Neanderthals.
Byron, it is confusing, and I think it is because they are using different baselines to calculate the percentages. Such things rarely get translated well in popular science accounts.
@iheartneanderthals I think the point is that with certain population situations that certain genes can be eliminated entirely from a population, even with a common ancestor. Interbreeding seems likely to me, however I'm pretty sure the researchers supporting the population model understand genetics well enough to come up with a plausible scenario where evolution of the population can also explain the differences.
It could also be that those genes were needed to live in the cooler European environment, so modern humans that went there simply evolved the same sort of genes that Neanderthals did. Convergent Evolution, as it were.
I have heard the percentage of possible Neanderthal gene in Asian populations, but cannot remember it at the moment. It was a bit different from Caucasian percentage.
"We share 98% of our DNA with chimps; only 2% is different, and chimps are another species, nowhere near as close to us as Neanderthals."
I've read that female and female genes differ by more than 2% .
Tony, Bingo! But then again you and I certainly need no cold weather adaptations in this sweltering hole ... er ... I mean Dallas! :c)
Yeah guys and which 4%? The ones that trait for Oxygen metabolism, endoskeleton and mammalian birth? That's pretty much the same as every warm-blooded animal on earth.
Ahh, science. What a whore.
Voice, I could certainly use some cold weather, or a cold beverage, right about now. Though the rain has been nice to cool us a few degrees, it upped the humidity.
Interesting and Very complicated to understand.
When adding up all the responses in this thread.....it just goes to show you.....we'll have sex with anything and everything....and yes, that goes for those in Detroit, the family pet and Bill Clinton.
JEAN 1002429---TY most intelligent part of the total above narative! I see a great many ape looking knuckle draggers every place I travel to! We had to have interbreed it is just good olde Friday nite at the slop shoot! But who cares? it was so long ago---better concern ourselves with getting jobs back from other countries, getting dept paid off, removing corrupt politicians, taking back a Constitutional Country, get obama OUT!
Wake up America.
I think someone needs to stop drinking from the Faux punch bowl.....
Ok Keith, we'll leave the myopia to you as long as you can leave the science to those who care.
Another loser with tiny penis syndrome who is having trouble dealing with reality. We feel your pain tiny.
Again, more conclusive proof that organized religion and belief in a magical god is nothing but a con job on the less intelligent and emotionally needy.
Romney and Ryan have announced they are completely opposed to sex with Neanderthals outside of heterosexual marriage. (Sorry, just could not resist.)
Pale skin, red hair??
Alas, now we have identified the reason that "Gingers have no souls!!"
E. Cartman
Q: What's the most implausible thing about the Harry Potter stories?
A: A ginger with TWO friends.
I guess they're still trying to explain that missing link theory, in a sense. Seems to me, there was some DNA engineering going on a long time ago. As humans, our DNA may appear to be the same, but we have different groups of people. We're the same, but we're still not the same. And we follow different religions. Any missing "link" is more than likely soemthing they have still not found within the human DNA. The intervention of Aliens using a basic model and "tweaking" makes more sense than about anything else. Really no one religion can explain it, science can't or won't, (or won't tell us) Darwinism and evolution doesn't hold up.
There's no evidence of "DNA engineering" to the contrary the evidence strongly points towards common ancestry. with regards to races that's just a matter of evolution applied to humans based on regional climates, the genetic differences this has caused is truly insignificant.
Regarding the "missing link" it's just a meaningless diversion propagated by creationists, there will always be missing links because not every corpse fossilizes and even if it did there's no way to know exactly where it is, we don't exactly have the technology to remove the entire surface of the earth and sift through it like we're panning for gold in the form of fossils.
A "missing link" is, or was, key fossils in biological transitions as regards the science. I think the concept has been dropped because it isn't really relevant today, it is a matter of resolution when you have more complete phylogenies.
The original concept has been changed and misused by creationists to erroneously imply that the disappearance of your grandfather and the failure of his burial makes him a "missing link". In such cases the pathways are still resolved, you are a human regardless.
There isn't any key transitional species here, the hominins fossil finds transition nicely on curves of increasing brain weight et cetera. The unresolved areas is the ancestry of H. floresiensis, other cryptic species (the African introgression), and the hominin root.
In the same PNAS as this paper there is a paper where they have observed homininae mutational rates by a new method. Earlier they estimated those on dated splits and, I assume, mithocondrial DNA. Now they have used nuclear DNA (I think) and sampled extant material (fecals et cetera) to establish generation and mutation rates.
Turns out, surprisingly, chimps are a lot like us, their generation ages average some 25 years (IIRC). In any case, the better data pushes back the splits chimps/humans and gorillas/humans a few million years. This places early hominin finds well within the time period after the splits.
Ironically, the truly low resolution in observation is all on the chimp lineage. Their forssil record is abysmal.
There is one little element that those looking for a "missing link" seem to ignore. They keep spouting about some half ape half human creature when the reality is it does not exist for a simple reason .... homo sapien did not evolve from an ape creature, it is an ape creature and all apes evolved from a common ancestor.
According to Dawkins Dennis, that is what happened, we and the other apes diverged from a common ancestor about 6 million years ago.
And there are no missing links...every fossil found has been a link. We simply haven't found all the fossils yet, be they hominid or otherwise.
I think the researchers missed the whole
senario. There happened to be a Neanderthal
by the name of Billy Clinton. At that time they
did now have zippers and underpants so Billy
just lifted has loin cloth and hybridization anything
with a pulse including monkeys and apes. Therefore
the democratic race was conceived. Check it out.
men would stick it in a bowl of soup if it were warm.
crude, yes, but completely correct ;)
mmmmmmmm soup......
*Adds "soup" to grocery list*
LMAO!!!!! :D
Or an American pie.
mmmmmmmmm pie.....
I don't think there is much that modern homo sapiens hasn't had sex with, so I isn't much of a stretch.
Of course ancestral population structure was looked at by Paabo et al. But the factors and events that had to balance the genes was much more unlikely.
Paleontologist John Hawks (2010):
"African variation is great, and if you imagine that some variation might have once existed in northeastern Africa and was subsequently lost within African populations, that might look like admixture with archaic humans outside of Africa.
This line of argument is now special pleading. Why would we posit a cryptic mystery population in Africa, which happens to look genetically identical to Neandertals, but has subsequently disappeared? A big fraction of deep genealogies outside Africa really are in Neandertals. By far the simplest explanation is that today's non-Africans got them from ancient non-Africans. This is no surprise -- that's where the data have been pointing now for five years." [ ]
"This is, of course, what was done in the case of the Neandertal genome -- a specific population model was significantly favored by the data, and alternatives that did not include population mixture were demonstrated to be so unlikely as to be essentially impossible." [ ]
More interesting perhaps is the recent work that shows, with different methods, there have been at least one similar introgression event in Africa at about the same time it happened in Europe (Neanderthals) and later, in Asia (Denisovans). So at some point there were 5 different hominins (with H. floresiensis) sharing Earth.
The links got stripped. Let me try again:
"">1st quote.
a>.
Nope. Well, you can google "Hawks neanderthals" and get to his web pages.
Yes, it didn't make much sense to me either. Since Africans are descendants of the same common ancestor, the absence of the common genes in them would still be unexplained.
Somewhere in the midst of all the research a scrawny young geneticist with horn rimmed glasses taped together at the bridge longs for a NILF and mourns the fact he won't get the opportunity to meet one.
Perhaps Neanderthal DNA could be located, a few specimens could be created and released into the world. We would soon have the answer...and the answer will be no surprise to anyone outside the realm of socially isolated nerds.