The Denisovan discovery thread

Adam Khor

http://www.sci-news.com/genetics/humans-interbred-denisovans-twice-05822.html

Wibbs

IIRC the Neandertal admixture happened at least a couple of times too. Asian folks have a slightly different set of genes from them compared to Europeans. There seems to have been broadly three "major" events: in the Middle East when we first met each other, a more easterly event in west Asia and a more westerly event in Europe(along with the occasional jiggy jiggy that likely went on a few times).

The Denisovan folks are fascinating. If for nothing else because all we have of their DNA is from tiny fragments of bone found in one cave. What did they look like is one question. I suspect a fair number of bones in Asian research centres and universities are them. Or maybe not. The Red Deer People from around 12,000 years ago are extremely odd looking folks.

Adam Khor

I may be completely wrong here but, I do remember reading something about the Chinese being adamant that the traditional human family tree is wrong and that they are in fact descended directly from Homo erectus (?), and thus definitely separate from the rest of the human species...
Googling for Red Deer people reconstructions gives these results:



Would love to know your thoughts...

Capt'n Midnight

Adam Khor wrote: »

I may be completely wrong here but, I do remember reading something about the Chinese being adamant that the traditional human family tree is wrong and that they are in fact descended directly from Homo erectus (?), and thus definitely separate from the rest of the human species...

Reminds me of Piltdown Man or the how the English are one of the tribes of Israel. Or the Romans being descended from the Trojans.

I like some Chinese films, but always there's the message about not upsetting the legitimate state sponsored status quo.

All moot anyway until more DNA evidence living or dead mounts up. And nowhere near as bad as the old soviet biological sciences.

Adam Khor

Apparently this was found in China's Shaanxi Province in 1978. Estimated at about 260.000 years. I suppose (hope :B) Wibbs knows more about it?

Wibbs

I don't TBH. That's of a fair age. Roughly contemporaneous with Homo heidelbergensis in Europe, so maybe the east Asian equivalent? Much larger brow ridges though.

Adam Khor

The orbits look huge!

Adam Khor

At least that's what's been suggested based on DNA. If so, it is further evidence (as if more was needed) that hominins of different species were interbreeding.

https://www.nytimes.com/2018/08/22/science/neanderthals-denisovans-hybrid.html

Wibbs

Not too surprised to hear this. Neandertals and Denisovans were more related to one another than they were to us. The genetics seem to show that the common ancestor of Neandertals and Denisovans came out of Africa(and split with our common ancestor) around 500,000 years ago. The finds in Atapuerca in Spain at around 350,000 years ago show this mix.

It seems in very basic terms that at some point there was an East/West split and the Western folks became Neandertals, the Eastern became Denisovans. An added complication was that at least once, if not a few times early Modern Human groups out of Africa wandered into the Middle East and got the groove on with the locals and added some of our DNA into the mix.

Though we don't know what Denisovans looked like, I suspect the Neandertal like fossils found in Asia(China mostly) were them. That they looked more Neandertal than Modern Human. Then again if you go back say 100 odd 1000 years ago, we look more like them too. We have a suite of features that mark us out as Moderns(large globular braincase, protruding chin, swept forward cheekbones), but they were not as marked as they are in people today. We had much larger brow ridges back then for a start. A few years ago a Wiki page on Neandertals actually showed a pic of an early Modern skull from Africa and it stayed unedited for ages, which kinda illustrates this

I would suspect that a Denisovan, or Neandertal, or Modern of that era, upon meeting one of the others, would beyond things like maybe different skin tones recognise them as being like them more than not. A modern of today would stand out far more. Actually I suspect that even though we're far more interrelated today the diversity of external physical features in people today across populations and geography might even be higher than back then. That say a 6th century African from the Congo who had never seen a European would get more of a shock at encountering a 6th century Swede - and vice versa - than a Denisovan would upon meeting a Neandertal.

gozunda

Observed differences physical and other relevant to the above example of Swedes and Congolese may also be ascribed at least in part due to the (up to 6%) Neanderthal genetic contribution to modern European genomes.

Another interesting aspect of these discoveries is that it would appear that those Homo sapiens derived populations who migrated appear to have spent more time 'out of Africa' than 'in Africa'.

Given that the estimated timeline indicates that modern humans evolved from most likely recent common ancestor within the last 200,000 - 300,000 years - more recent discoveries have uncovered remains of a modern human who lived 177,000 to 194,000 years ago from the Misliya Cave in Israel.



See: https://www.natureasia.com/en/nmiddleeast/article/10.1038/nmiddleeast.2018.15

Wibbs

gozunda wrote: »

Observed differences physical and other relevant to the above example of Swedes and Congolese may also be ascribed at least in part due to the (up to 6%) Neanderthal genetic contribution to modern European genomes.

Possibly, though many of those differences emerged well after Neandertals and other cousins disappeared. EG Blonde hair(around 12,000 years ago), blue eyes and European pale skin(30-15,000 years ago) that we'd recognise today. So it seems unlikely we got them from Neandertals. Also Asians have a different suite of genes for pale skin. If the genetic locks are correct of course. I'm personally dubious about some of them myself and I think it's not the reliable tool it's often held up to be.

Now it is possible non African folks got some features from Neandertals(and Denisovans). They did get things like faster healing, quicker clotting and various immune system changes. Some Neandertals show genes for pale skin, light, even red hair. Some were darker. Their pigmentation seems to have varied over time and place, which is understandable*. They were around for hundreds of thousands of years and changed in their bones in that time, so not a shock to find they changed in other ways as local adaptations. After all as we see above many modern human physical changes appear to be quite "recent" and spread quickly. Their red hair mutation is different to the modern one however. I haven't read much definitive on the pale skin mutations. If they're the same or close to modern Europeans then they might be the source. Or it could be a similar adaptation to similar environmental stresses. In light skin's case, vitamin D production in higher latitudes.







*one thing I've mused on is that if you look at the pigments they collected and we assume they were often used as body art, then they tended to collect pigments that were dark in colour, blacks, dark reds and the like. Pale skin is a far better canvas for that palette. If you look at very dark peoples today who use body paint they instead choose whites and yellows and light reds. Makes sense.

Adam Khor

Wibbs, whenever I read one of your answers, I get curious about the anatomical/physiological differences between today's races and try to read more on the subject, only to be frustrated by the lack of objective sources out there Almost all websites that discuss the matter end up being racist propaganda or ancient alien conspiracies.

I can´t be the only one tho who notices how zoologists split and name separate species of non-human animals based on differences far more insignifcant than what you see between one human group and another. Yet most scientists seem afraid to use the word race, let alone subspecies (as Darwin suggested), when applied to the human genus.

I was reading the other day about African pygmies and how they apparently diverged from other subsaharian Africans tens of thousands of years ago- some studies apparently date the divergence at 90.000 to 150.000 years ago, which is just mind boggling. (BTW, this is just something I read recently and for all I know may be wrong, as I'm not at all an expert on this subject; however, all the sources I've checked agree that the split was very early indeed, even if the dates given seem to vary).
I also find it intriguing that the pygmies' small size and short lifespan (16-24 years) seem to be genetically programmed rather than a result of say, poor nutrition and disease.
Other groups that live in the same areas consider pygmies to be non-human, and thus have no qualms about hunting them and eating them as they would monkeys or chimps.

I also remember reading at one point (again, not sure if true, please correct me if not) that the San/bushmen people also diverged from other groups tens of thousands of years ago AND apparently the result of their mating with other people tends to be sterile.

If this were all true, wouldn´t it mean mankind is made up of more than one single species even today? Would the difference between us and Neanderthals /Denisovans be so much greater than the difference between say, pygmies and Europeans?

Wibbs

"Species" has always been a vague definition anyway. Subspecies ditto. I would see all modern humans as one species, but with distinct populations within, with quite the bit of overlap for most, less overlap for others. IE those who are more isolated geographically or culturally. Pygmies would be one such of the latter populations. They became genetic isolates over time, with distinct genotypes and obviously phenotypes. Looking at their genetics though there is quite the bit of back and forth from outside populations. Ditto for the San Bushmen. Indeed the latter show genes that seem to have come from all populations European or west Asian about 10,000 years ago IIRC. This stuff can happen quite "quickly". EG the study into Irish Travellers that found distinct genetic markers with them when compared to the wider Irish population. Basically because over a few centuries they were more culturally isolated. We see similar with some European Jewish populations, where because culturally they tended to marry within the population and the faith some have distinct genetics and higher frequencies of some genetic mutations, both good and ill. Even there the bulk of European Jewish genes are European in origin rather than Middle Eastern, so they certainly "married out" enough for that to occur.

That's been a consistent thing with modern humans. As well has having kids with other humans we met on our travels we also traveled backwards and had kids with people from the areas we came from. It wasn't all one way, or as simplistic as out of Africa is seen in the popular mind. "We" came from a group that appear to have been around in the general area of Ethiopia. However that same bunch also went south and west within Africa and other Africans went east and north. It's all extremely fuzzy. And that's before the migrations that started but went nowhere, but who left some genetics going on in the areas they abandoned.

Another aspect is genetic isolation. Neandertals and Denisovans were separated from their African roots and each other for hundreds of thousands of years, with very different environmental stresses and were rare in the landscape as apex predators will be and had less overlap and migrations, so were quite "inbred" at times. This led to distinctive genes and physical features, which themselves varied over time. The "classic" Neandertal runs from about 150,000 to 80,000 years ago. Before that they were more robust, after more gracile. They were following kinda the same trajectory as moderns in this. This makes them more of a "subspecies" of each other. One that could reproduce with each other, because of close common ancestry, but more different than peoples today. Indeed some researchers reckon that Neandertal/Modern pairings could have kids, but their fertility was compromised. Fine the first generation, but second and third could have problems. IIRC because they found a very strong selection against Neandertal reproductive genes or something like that.

I'd not heard of any fertility problems between San folks and their neighbours(or the various Pygmy populations). Then again how many from outside are getting together with locals? I would suspect in areas of overlap they surely must be? I have read down the years of Europeans(nearly all men) having kids with Papuan/Amazonian/various African tribes/Tibetan/Australian Aboriginal women with no problems and Europeans should be more genetically isolated than local populations. I'd be surprised to find fertility problems TBH. The vast bulk of our shared genetic legacies are at most within the last 50-80,000 years, not the 200,000 years compared to Neandertals et al. Personally I'd bet the farm those to do with fertility are within pretty much the same ages and the same worldwide.

As for distinct physical features. This has long been a thing in humans, even within the same population. Europeans are about the best example of this in modern terms. They have the widest range of skin tones, eye colour and hair colour and texture of any population on the planet. Even within the same family you can have a blonde and a redhead with blue eyes or brown. Go back much further and consider the Homo Erectus(who I would see as not human) they found in Georgia. This really threw researchers as the wide range of physical features in near every skull dug up, would if they had been found on their own in different areas might well have been labelled as different subspecies, even distinct species. They were that different, yet they all came from the same place and within a very close timeframe.

Adam Khor

Wibbs wrote: »

consider the Homo Erectus(who I would see as not human) they found in Georgia. This really threw researchers as the wide range of physical features in near every skull dug up, would if they had been found on their own in different areas might well have been labelled as different subspecies, even distinct species. They were that different, yet they all came from the same place and within a very close timeframe.

So, to clarify, you would categorize both Neanderthals and Denisovans, I assume, as human, but not Homo erectus? Why, though? When does one start being human?

I do remember reading that Homo heidelbergensis was probably not a thing...

Adam Khor

Relevant to this thread, a peek inside the Denisova cave where the remains were found AND apparently needles and some supposedly Denisovan-made bracelets were found there too? :eek:

https://siberiantimes.com/science/profile/features/peek-inside-the-siberian-cave-where-inter-species-love-child-denny-lived-90000-years-ago/

Wibbs

Adam Khor wrote: »

So, to clarify, you would categorize both Neanderthals and Denisovans, I assume, as human, but not Homo erectus? Why, though? When does one start being human?

Oh agreed it's arbitrary on my part. It's a hard question and it's an extremely fuzzy point to mark. I'd maybe nail it down to abstract cultural thinking, so if the finely made quartzite biface they found in Northern Spain among the remains of a number of Heidelbergensis bones was an "offering" that would be a plus point for "Human". Neandertals had pigments and stone "circles" in caves and cave paintings so they qualify. I suspect similar in play for Denisovans.

On that point...

Adam Khor wrote: »

Relevant to this thread, a peek inside the Denisova cave where the remains were found AND apparently needles and some supposedly Denisovan-made bracelets were found there too? :eek:

Yeah I remember reading that alright AK, but only there and in a couple of Russian media outlets. To find needles among non Modern Humans would be a big story, to find a finely made bracelet like that, using techniques and a mindset that doesn't show up until damn near neolithic times would be absolutely huge, yet the story doesn't show up anywhere else that I can find. Which is odd.

Adam Khor

The bracelet thing does seem very confusing...

Adam Khor

https://www.forbes.com/sites/jenniferraff/2019/02/02/new-dates-reveal-which-ancient-hominins-were-living-in-denisova-cave-and-when/#6c776ff5fd86

NoLifeLine

Thats an interesting article. Make you wonder what life was like for those early homonins.

Cozy little cave

Ardillaun

I wonder how many caves there were in the locality that were as inhabitable as that one? It seems to have been a popular spot.

Adam Khor

Not just hominins but also large carnivores like lions and hyenas seem to have used the caves (or at least lived in the vicinity)

Adam Khor

https://www.mnn.com/earth-matters/wilderness-resources/stories/90000-year-old-girl-was-ancient-human-hybrid

Adam Khor

https://www.sciencenews.org/article/first-fossil-denisovan-skull-cave-siberia

odyssey06

To my untrained eye they would look less like homo sapiens than neanderthals? Skull seems larger or that could be specimen size?

Wibbs

Well they've only a part of the skull O, so there's a bit of conjecture going on at this stage. The fragment is thicker than a moderns or Neandertals, but it could be a very robust individual, they could look like us, or Neandertals but just with thicker cranial bones. Until someone finds a more complete skull we won't know.

I would strongly suspect we already have more examples of them in museums and university collections. There are quite the number of Asian skulls that have been found from the time periods Denisovans lived. Given they seem to have crossed paths that resulted in having kids together with both Neandertals and modern humans at least three times I would be truly shocked if a few of the existing Asian archaic skulls weren't them.

In the link they note that the skull thickness is more like Homo Erectus which they didn't expect, yet the skull found in Henan China from around 100,000 years ago had researchers all a quiver because it seemed to share both Erectus and Sapiens features.


Then there's the much older Dali man skull which looks very archaic, but also has features that are similar to Sapiens at a time when no sapiens had any business being there.



And here's another lad found elsewhere in China, from around 100,000 years ago that shares features with both sapiens and neandertals.

Though personally I'm very dubious of such descriptions. Just because a species has what look like sapiens features, doesn't mean it has anything to do with our line of sapiens, or is indicative of sapiens in isolation.

In any case any one of them might be Denisovans hiding in plain sight.

Wibbs

The more I think about the Denisovan "enigma" the more I am convinced that the Asian skulls above like Dali man and others found in high enough numbers for archaic peoples across a period of 200,000 years in date are Denisovans, or pre Denisovans. They all show a suite of unique features in their morphology(though I'm somewhat dubious when morphology is seen as the be all and end all. The Georgian Erectus finds with their incredible variation in the same species should have put that mostly to bed).

After all the percentage of their genes found in modern populations in that neck of the woods is higher than Neandertal there and in Europe, so they were around for a long time and there were enough of them about to have kids with both us and Neandertals(which also seem to have had a more easterly range than previously considered). That these Asian skulls that never really seemed to quite fit with existing theories because of their odd mix of "archaic" and "modern" features, yet are similar enough to each other really does look like these folks were hiding in plain sight all along.

And then you have the Red deer people from only 12-14,000 years ago...



With their Darth Vader cheekbones, underdeveloped chin, large modern like brain case and more modern lack of brow ridges, all bets are off. Sadly no DNA has so far been found for them.

It was Asia which was once the focus of looking for our earliest ancestors in the early days of the field, before Africa took over. I suspect our focus will shift back there for a time. It seems there were lots going on. I'd be willing to bet that Erectus lasted longer there as both a "pure" form and as a mix with others and was involved more in local adaptations in local species. It's exciting stuff. If you had told me twenty years ago that there were at least another two lineages to be found in relatively recent human evolution I'd have been surprised and yet here we are.

Adam Khor

The fossil record of apes in general seems to be pretty frustrating- lots of remains but almost always fragmentary. Gorillas and chimpanzees have practically no fossil record- there's lots of pieces missing from that puzzle. Who knows what strange gorillas and chimps and things in between lived in Africa during the Plio-Pleistocene?

Likewise, I wouldn´t be surprised if there were still more hominin linneages to be found all over the Old World, considering the latest finds.

Adam Khor

Ok, some very interesting discoveries being made right now about Denisovans so I thought they deserved their own thread too.

A large jaw and teeth belonging to a Denisovan has just been described from Tibet, where it was found in the 1980s by a Buddhist monk who went into the cave to pray.

https://www.newscientist.com/article/mg24232283-700-major-discovery-suggests-denisovans-lived-in-tibet-160000-years-ago/







The jaw is at least 160.000 years old, earlier than any modern human remains found in the Tibetan Plateau (middle Pleistocene). The size, morphology and collagen protein analysis results are consistent with the already known Denisovan teeth from Siberia.
The find proves that Denisovans were very widespread, that they reached the Tibetan plateau long before H. sapiens, and may also explain the presence of some ancient tools found in the region. It also suggests Denisovans developed the necessary adaptations to survive in high altitude, low oxygen habitats.

Also, and this is solely my imagination going wild, but I can´t help but to associate the remains of these large, ancient hominins with the ancient Tibetan folklore regarding the mi rgod, which was a hairy, ape-like wildman creature according to pre-Buddhist Tibetans, and which would eventually give rise to the Yeti mythos.

If, as we have often imagined, the stories of woodwoses, trolls, ogres and other wild-men of the woods from European folklore have their origin in cultural memory of late surviving populations of Neanderthals, could the Denisovans be similarly behind the mi rgod, yeti, almas etc of the Asian mountain ranges?

Adam Khor

Morphology of Denisovan phalanx closer to modern humans than to Neanderthals:

https://xherald.com/2019/09/05/morphology-of-the-denisovan-phalanx-closer-to-modern-humans-than-to-neanderthals-science-advances-2/

The researchers matched the missing fragment to the original by using DNA extraction and sequencing techniques to capture its entire mitochondrial DNA sequence.

“The digit was a fifth finger bone from the right hand of an adolescent female Denisovan who likely died at about 13.5 years old,” they said.

Dr. Bennett and co-authors also reanalyzed scans and photographs of the Denisovan finger fragments and compared them with finger bones from Neanderthals, as well as Pleistocene and recent modern humans at various stages of development.

“We show that their dimensions and shape are within the variability of Homo sapiens and distinct from the Neanderthal fifth finger phalanges,” the scientists said.

“Researchers should take caution when identifying potential Denisovan skeletal remains, since they may appear more similar to modern humans than to Neanderthals,” they added.

Adam Khor

First reconstruction of a Denisovan, based on its DNA.

https://www.livescience.com/Denisovan-facial-reconstruction-dna-methylation.html





I guess we won´t know how on point until a complete skull is found!

Wibbs

While that's some interesting and impressive science on the gene expression front, IMHO it's yet another example of major conjectural leaps springing from meagre actual science that tends to infect the study of our ancestors.