Modern humans bred with 5 archaic human species?

Brian G Turner

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The idea that modern humans bred with Neanderthals is a relatively recent development, and over the past couple of years it appears we bred with another and more mysterious group of archaic humans known as Denisovians.

However, recent genetic research suggests there may have been three more different human species that modern humans interbred with, particularly in Asia:

 

Brian G Turner

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I often thought the old idea that one hominid neatly evolved into another was likely to be oversimplified. Even still, I'm still surprised at the number of potential interbred "species" - Neanderthals was a given, and possibly a couple more - but 5?!
 

BAYLOR

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I often thought the old idea that one hominid neatly evolved into another was likely to be oversimplified. Even still, I'm still surprised at the number of potential interbred "species" - Neanderthals was a given, and possibly a couple more - but 5?!


In the past the Human species was probable alot more diverse the we can imagine today.
 

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I often thought the old idea that one hominid neatly evolved into another was likely to be oversimplified. Even still, I'm still surprised at the number of potential interbred "species" - Neanderthals was a given, and possibly a couple more - but 5?!
I guess because of the sparsity of evidence it's hard to tell how large or small an area each group actually inhabited and therefore hard to imagine how much interaction there was likely to be between them. I really wonder if this is really any more significant than say a modern Caucasian and an Asian having children. Are the genetic differences between these ancestral groups any greater than between our more modern groups? I'm not trying to be facetious I honestly don't know enough about it to know if that's a silly question or not! :unsure:

ETA: or maybe it's an indication of just how much travel early humans did!
 

Brian G Turner

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Are the genetic differences between these ancestral groups any greater than between our more modern groups?

From my reading, I get the impression that defining "species" is a lot harder that most people realize. The difference between modern humans and some of those groups might be so small that I wouldn't be surprised if some biologists are already developing a more inclusive definition of homo sapiens. :)

There's a course at the OU on speciation I'd love to do but I won't have time for - however, my daughter has brought her bioscience textbooks home with her from uni, and I've already baggedone for my summer reading. :D
 

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There's a course at the OU on speciation I'd love to do but I won't have time for - however, my daughter has brought her bioscience textbooks home with her from uni, and I've already bagged one for my summer reading. :D

And my kids think I'm a nerd?! I'm so far behind of your league it is not even funny.
 

Robert Zwilling

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Our physical appearances make us look a lot more different than we are. Apparently there are far more "internal" features that operate the body compared to the physical appearance features. Take random people and sample the genes and more likely the people who look the least alike will have more in common with each other than those who look the most alike. Take a couple a hundred people and sample them for Neanderthal genes and around 2 percent of the genes will be Neanderthal in each person. However when you compile a list of all those Neanderthal genes it will have a very large assortment of different Neanderthal genes. It turns out each person has a different 2 percent sampling. I have no idea if the Denisovian genes we carry have the same scrambled assortment. The human ancestry tree covers a lot of branches that eventually disappeared. It does literally look like a tree and as the last one standing we are the trunk. Because of the similarity of all those hominoids just about all those branches could produce offspring when they crossed paths. There were branches going for long periods of time picking up whatever they could from the shorter branches that disappeared. Being the last one standing might be a dubious distinction as that means there is no other "human" group to carry on after us.
 
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Vertigo

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I'm still left wondering whether the others really died out and became extinct or were just absorbed. However I guess the geneticists can tell the difference from the traces. ie. if we had equal percentages of each other groups genes then absorption would seem the most likely scenario but as, or so I believe, all the other group's genes are pretty small percentages. I guess that indicates only a small amount of interbreeding and the rest just dying out. Out-competed I suppose.
 

Venusian Broon

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I'm still left wondering whether the others really died out and became extinct or were just absorbed. However I guess the geneticists can tell the difference from the traces. ie. if we had equal percentages of each other groups genes then absorption would seem the most likely scenario but as, or so I believe, all the other group's genes are pretty small percentages. I guess that indicates only a small amount of interbreeding and the rest just dying out. Out-competed I suppose.

This is just off-the-cuff so I may be wrong, but I seem to remember reading that the relationship between Neanderthals and Homo Sapiens was a bit more like that between donkeys and horses. So yes they could both procreate with each other and all combinations could produce offspring, but only Neanderthal males and Sapien females produced a fertile offspring. The other way round made an infertile 'mule'. (Or it might be the other way around). So I think there was that dynamic in any interaction. I think also there is evidence that Neanderthal fertility rates were lower anyway, so even if both groups kept each other at a distance, Sapiens would out-breed them over time. So even if it was all very friendly and peaceful, given that there would be huge numbers of modern humans at some point, and the fertility interaction between both species, the incoming humans would then easily swamp and absorb the Neanderthals.

What was the estimated percentage of Neanderthal DNA in Europeans? 4-5%?

So out-competed, yes. I think in the sense that it seems from the archeological record there was just much less innovation in Neanderthal tools and tech, and in the types of hunting/food opportunities they seem to have taken. (From tools and camp sites). We sapiens were able to exploit a lot more food sources and therefore survive in places that Neanderthals would never have thought of going. One must also remember that the Neanderthal is adapted to cold conditions. As the ice age receded they would, like a great many other animals more at home for those periods, at some disadvantage.

Again I may have misremembered, but I do believe there must have been some cultural interaction, as it appears there was a change in Neanderthal tool construction and artefacts in certain places and times, when we were either coming into an area or going through some innovation ourselves. But there seemed to be a limit on the type of things that were 'adopted' by Neanderthals, meaning either they didn't want them - or even they didn't understand what these new guys were doing - which is part of the suggestion in the book The Mind in the Cave, that Neanderthal minds and therefore their consciousness was actually quite different from our own. (Well, I say our. I'm European, so I assume I must have a bit of Neanderthal DNA in me somewhere. But you know what I mean! :))
 

Brian G Turner

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And my kids think I'm a nerd?! I'm so far behind of your league it is not even funny.

Financial necessity meant I spent the last couple of years stacking shelves in a supermarket. That drove me into continuing education, to ensure that the next time I need employment, I can work more to my potential. Just in case freelance writing doesn't work out for the long term. :)

The Mind in the Cave

Your comments are seriously interesting - are they mainly sourced from that book, or do you have a couple of others to recommend? :)
 

Venusian Broon

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Your comments are seriously interesting - are they mainly sourced from that book, or do you have a couple of others to recommend? :)

Yes, quite a lot that I splurged out was residual from that book! I gushed about it somewhere on the forums ;)

It's not really focused on Neanderthals and what happened to them but a key point of comparison is that, as far as we know, Neanderthals never made cave paintings. The speculation why, and why we did is brilliantly argued IMHO.

It really took me down a rabbit hole. (Turns out, perhaps, I'm a natural Shaman! Who'd have thunk it? :))

In terms of other books, I do have his next one 'The Neolithic Mind' on my TBR pile, and I'm fascinated what he and his co-author adds or brings to the table. I might have a search and see what other researchers are saying too.
 

Brian G Turner

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Just bringing this up again, because it was previously assumed that humans bred with Denisovians in Asia, and therefore their renmant genes are specifically present in Asian populations.

However, it's now been found that Icelanders also have Denisovian genes - one interpretation being that Neanderthals and Denisovians interbred as well, and the Denisovian genes got to Iceland through humans breeding with Neanderthals already carrying those genes:


Unexpectedly, they also found that Icelanders carry traces of Denisovan DNA, which was previously only thought to be present in East Asians and populations from Papua New Guinea. One possibility is that ancestors of the Neandertal population who mixed with modern humans had earlier also mixed with Denisovans.
 

Robert Zwilling

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Part of the problem with figuring out what happened is the concept that if there is no evidence of something happening, then it didn't happen. While at the same time this concept seriously downgrades the capabilities of the people being talked. People back in ancient times were probably less fearful of the world than we are today, which means they went a lot farther than we can imagine and did a lot more things than we give them credit for.
 

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It’s interesting. Just what is a ‘modern human’? If we have traces of DNA from these other ‘species’ aren’t we just a ‘melding’ of them all rather than a species in our own right?

It’s a bit like of talk of ‘us’ and ‘them’ with reference to the Norman Conquest. Isn’t ‘us’ now a mixture of both? The Normans didn’t pack up their bags and leave. They’re still here through inter-breeding.
 

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